Re: [ltt-dev] LTTng 0.149 adds experimental ascii output module
From: Mathieu Desnoyers
Date: Mon Jul 20 2009 - 14:48:23 EST
* Benjamin Poirier (benjamin.poirier@xxxxxxxxxx) wrote:
> Hello,
>
> Commit 04751bee05525eaa9310f4050b2f6ebdbcb62567
> "cpufreq-cleanup-cpufreq_add_dev" in the lttng tree breaks the build on
> machines without CONFIG_SMP:
> drivers/cpufreq/cpufreq.c: In function âcpufreq_add_devâ:
> drivers/cpufreq/cpufreq.c:957: error: âmanaged_policyâ undeclared (first
> use in this function)
> drivers/cpufreq/cpufreq.c:957: error: (Each undeclared identifier is
> reported only once
> drivers/cpufreq/cpufreq.c:957: error: for each function it appears in.)
> drivers/cpufreq/cpufreq.c:1007: warning: label âerr_unlock_gov_mutexâ
> defined but not used
> make[2]: *** [drivers/cpufreq/cpufreq.o] Error 1
>
Thanks for the report, I'll merge patch
commit 2381f2a2d3b329313b375bc0bf5df34802b9b4ba
Author: Dave Jones <davej@xxxxxxxxxx>
Date: Wed Jul 8 16:14:23 2009 -0400
[CPUFREQ] Fix compile failure in cpufreq.c
In my tree for 0.150.
Mathieu
> -Ben
>
> Mathieu Desnoyers wrote:
> > Hi,
> >
> > I completed the work needed to add an ascii output to LTTng last week.
> > This effort has been initiated by Lai, but needed some polishing to
> > correctly interact with the LTTng ring buffer synchronization.
> >
> > I decided to release this feature as "EXPERIMENTAL", given it still
> > needs some enhancements and testing. Those are explained in the TODO
> > comment at the beginning of ltt/ltt-ascii.c. One of the main items would
> > be to merge-sort events on a per-trace basis, so people can select
> > which channel they want using the per channel "enable" file and then
> > simply have a single ascii output for the channel collection.
> >
> > This patch is integrated in LTTng 0.149. I plan to start going through
> > these TODOs when I finish writing my thesis, in a few weeks.
> >
> > Sample output of the kernel channel:
> > (patch below)
> >
> > # cat /mnt/debugfs/ltt/ascii/trace/kernel
> > event: softirq_raise: cpu: 5 time:00000501376636750494 softirq_id 1
> > event: softirq_raise: cpu: 5 time:00000501376636752660 softirq_id 6
> > event: irq_exit: cpu: 5 time:00000501376636753002 handled 1
> > event: irq_entry: cpu: 5 time:00000501376644750066 ip 18446744071564245255 handler (null) irq_id 239 kernel_mode 1
> > event: softirq_raise: cpu: 2 time:00000501376639351302 softirq_id 4
> > event: irq_exit: cpu: 2 time:00000501376639356114 handled 1
> > event:sched_migrate_ta: cpu: 2 time:00000501376639369422 pid 19862 state 2 dest_cpu 2
> > event:sched_try_wakeup: cpu: 2 time:00000501376639371060 pid 19862 cpu_id 2 state 2
> > event: timer_set: cpu: 2 time:00000501376639380420 expires 4357539470 function ffffffff80400690 data 18446612150560638464
> > event: sched_schedule: cpu: 2 time:00000501376639389012 prev_pid 0 next_pid 19862 prev_state 0
> > event: page_fault_exit: cpu: 2 time:00000501376639394466 res 516
> > event: syscall_entry: cpu: 2 time:00000501376639458606 ip 140218697167927 syscall_id 11
> > event: syscall_exit: cpu: 2 time:00000501376639489320 ret 0
> >
> > Mathieu
> >
> >
> > LTTng text output module, basic features working
> >
> > Here is the ltt-ascii module working, with still a few TODO left. Therefore,
> > still considered experimental.
> >
> > See Documentation/lttng.txt.
> >
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
> > CC: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> > ---
> > Documentation/lttng.txt | 35 +++
> > include/linux/ltt-channels.h | 2
> > include/linux/ltt-relay.h | 3
> > include/linux/ltt-tracer.h | 29 ++
> > include/linux/marker.h | 4
> > kernel/marker.c | 8
> > ltt/Kconfig | 3
> > ltt/ltt-ascii.c | 432 +++++++++++++++++++++++++------------------
> > ltt/ltt-relay-alloc.c | 8
> > ltt/ltt-relay-irqoff.c | 17 +
> > ltt/ltt-relay-locked.c | 17 +
> > ltt/ltt-relay-lockless.c | 17 +
> > 12 files changed, 386 insertions(+), 189 deletions(-)
> >
> > Index: linux-2.6-lttng/include/linux/marker.h
> > ===================================================================
> > --- linux-2.6-lttng.orig/include/linux/marker.h 2009-07-20 09:27:27.000000000 -0400
> > +++ linux-2.6-lttng/include/linux/marker.h 2009-07-20 09:27:28.000000000 -0400
> > @@ -237,8 +237,8 @@ extern int marker_probe_unregister_priva
> > extern void *marker_get_private_data(const char *channel, const char *name,
> > marker_probe_func *probe, int num);
> >
> > -const char *marker_get_name_form_id(u16 channel_id, u16 event_id);
> > -const char *marker_get_fmt_form_id(u16 channel_id, u16 event_id);
> > +const char *marker_get_name_from_id(u16 channel_id, u16 event_id);
> > +const char *marker_get_fmt_from_id(u16 channel_id, u16 event_id);
> >
> > /*
> > * marker_synchronize_unregister must be called between the last marker probe
> > Index: linux-2.6-lttng/ltt/ltt-ascii.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/ltt-ascii.c 2009-07-20 09:27:26.000000000 -0400
> > +++ linux-2.6-lttng/ltt/ltt-ascii.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -8,32 +8,30 @@
> > */
> >
> > /*
> > - * TODO :
> > - * This file is work-in-progress. It should be adapted to the new internal API
> > - * for readers. The algorithm is :
> > + * TODO
> > *
> > - * sleep (for polling mode) or wait on a reader wait queue.
> > - * wait for all buffers to be ready for read
> > - * when ready, get subbuf (for all subbuffers)
> > - * merge sort reads by timestamp
> > - * a read is done with get_offset/get_consumed to know
> > - * - Where to read
> > - * - If buffer is empty
> > - * - If buffer has reached EOF
> > - * put subbuf when read ends for a subbuf
> > - * while buffers are not both finalized and empty.
> > + * - Automate periodical switch:
> > *
> > - * struct ltt_relay_cpu_iter and struct ltt_relay_iter should be adapted
> > - * to work on buffer "consumed/write" offsets rather than a single "offset"
> > - * variable.
> > - *
> > - * The new debugfs file "switch_timer" receives a timer period as parameter
> > + * The debugfs file "switch_timer" receives a timer period as parameter
> > * (e.g. echo 100 > switch_timer) to activate the timer per channel. This can
> > * also be accessed through the internal API _before the trace session starts_.
> > * This timer will insure that we periodically have subbuffers to read, and
> > * therefore that the merge-sort does not wait endlessly for a subbuffer.
> > + *
> > + * - If a channel is switched and read without data, make sure it is still
> > + * considered afterward (not removed from the queue).
> > + *
> > + * - Create a ascii/tracename/ALL file to merge-sort all active channels.
> > + * - Create a ascii/tracename/README file to contain the text output legend.
> > + * - Remove leading zeroes from timestamps.
> > + * - Enhance pretty-printing to make sure all types used for addesses output in
> > + * the form 0xAB00000000 (not decimal). This is true for %p and 0x%...X.
> > + * - Hotplug support
> > */
> >
> > +
> > +
> > +
> > #include <linux/module.h>
> > #include <linux/ltt-tracer.h>
> > #include <linux/ltt-relay.h>
> > @@ -45,26 +43,51 @@
> > #include <linux/cpu.h>
> > #include <linux/fs.h>
> >
> > +#if 0
> > +#define DEBUGP printk
> > +#else
> > +#define DEBUGP(fmt , a...)
> > +#endif
> > +
> > struct dentry *ltt_ascii_dir_dentry;
> > EXPORT_SYMBOL_GPL(ltt_ascii_dir_dentry);
> >
> > -/* TODO : offset high bits, no disable., use API */
> > +struct ltt_relay_iter;
> >
> > struct ltt_relay_cpu_iter {
> > /* cpu buffer information */
> > struct rchan_buf *buf;
> > - size_t start_offset;
> > - size_t eof_offset;
> > + struct ltt_relay_iter *iter;
> > + int sb_ref; /* holding a reference to a subbuffer */
> > + long read_sb_offset; /* offset of the subbuffer read */
> >
> > /* current event information */
> > struct ltt_subbuffer_header *header;
> > - size_t offset;
> > - u64 tsc;
> > + long hdr_offset; /* event header offset */
> > + long payload_offset; /* event payload offset */
> > + u64 tsc; /* full 64-bits timestamp value */
> > u32 data_size;
> > - u16 chID; /* channel ID, const */
> > + u16 chID; /* channel ID, const */
> > u16 eID;
> > };
> >
> > +struct ltt_relay_iter {
> > + struct ltt_relay_cpu_iter iter_cpu[NR_CPUS];
> > + struct ltt_channel_struct *ltt_channel;
> > + loff_t pos;
> > + int cpu;
> > + int nr_refs;
> > +};
> > +
> > +static int is_subbuffer_offset_end(struct ltt_relay_cpu_iter *citer,
> > + long offset)
> > +{
> > + long sub_offset = SUBBUF_OFFSET(offset, citer->buf->chan);
> > +
> > + return (sub_offset + citer->header->lost_size
> > + >= citer->buf->chan->subbuf_size);
> > +}
> > +
> > static u64 calculate_tsc(u64 pre_tsc, u64 read_tsc, unsigned int rflags)
> > {
> > u64 new_tsc = read_tsc;
> > @@ -80,124 +103,158 @@ static u64 calculate_tsc(u64 pre_tsc, u6
> > return new_tsc;
> > }
> >
> > -static inline size_t calculate_offset(size_t offset, u16 chID, u16 eID)
> > +/*
> > + * calculate payload offset */
> > +static inline long calculate_payload_offset(long offset, u16 chID, u16 eID)
> > {
> > const char *fmt;
> >
> > if (!ltt_get_alignment())
> > return offset;
> >
> > - fmt = marker_get_fmt_form_id(chID, eID);
> > + fmt = marker_get_fmt_from_id(chID, eID);
> > BUG_ON(!fmt);
> >
> > return offset + ltt_fmt_largest_align(offset, fmt);
> > }
> >
> > -static void update_new_event(struct ltt_relay_cpu_iter *citer)
> > +static void update_new_event(struct ltt_relay_cpu_iter *citer, long hdr_offset)
> > {
> > u64 read_tsc;
> > unsigned int rflags;
> > + long tmp_offset;
> > +
> > + WARN_ON_ONCE(hdr_offset != citer->hdr_offset);
> >
> > - citer->offset = ltt_read_event_header(citer->buf, citer->offset,
> > + tmp_offset = ltt_read_event_header(citer->buf, hdr_offset,
> > &read_tsc, &citer->data_size, &citer->eID, &rflags);
> > + citer->payload_offset = calculate_payload_offset(tmp_offset,
> > + citer->chID, citer->eID);
> >
> > - citer->offset = calculate_offset(citer->offset, citer->chID,
> > - citer->eID);
> > citer->tsc = calculate_tsc(citer->tsc, read_tsc, rflags);
> > }
> >
> > -static void update_event_size(struct ltt_relay_cpu_iter *citer)
> > +static void update_event_size(struct ltt_relay_cpu_iter *citer, long hdr_offset)
> > {
> > char output[1];
> > const char *fmt;
> > + size_t data_size;
> >
> > if (citer->data_size != INT_MAX)
> > return;
> >
> > - fmt = marker_get_fmt_form_id(citer->chID, citer->eID);
> > + fmt = marker_get_fmt_from_id(citer->chID, citer->eID);
> > BUG_ON(!fmt);
> > - ltt_serialize_printf(citer->buf, citer->offset, &citer->data_size,
> > - output, 0, fmt);
> > + ltt_serialize_printf(citer->buf, citer->payload_offset,
> > + &data_size, output, 0, fmt);
> > + citer->data_size = data_size;
> > }
> >
> > -/* Is @value in the region [@left, @right) in a circular buffer */
> > -static int is_in_region(size_t value, size_t left, size_t right, size_t len)
> > +static void update_cpu_iter(struct ltt_relay_cpu_iter *citer, long hdr_offset)
> > {
> > - if (right < left)
> > - right += len;
> > - if (value < left)
> > - value += len;
> > - return value < right;
> > + if (unlikely((!citer->sb_ref)
> > + || is_subbuffer_offset_end(citer, hdr_offset))) {
> > + citer->header = NULL;
> > + return;
> > + }
> > + update_new_event(citer, hdr_offset);
> > + update_event_size(citer, hdr_offset);
> > }
> >
> > -static void update_cpu_iter(struct ltt_relay_cpu_iter *citer, size_t old_offset)
> > +/*
> > + * returns 0 if we get a subbuffer reference.
> > + * else, the buffer has not available data, try again later.
> > + */
> > +static int subbuffer_start(struct ltt_relay_cpu_iter *citer, long *offset)
> > {
> > - size_t len = citer->buf->chan->alloc_size;
> > - size_t eof_offset = BUFFER_OFFSET(citer->eof_offset, citer->buf->chan);
> > + int ret;
> > + struct ltt_relay_iter *iter = citer->iter;
> > + struct ltt_channel_buf_access_ops *buf_access_ops;
> >
> > - if (is_in_region(eof_offset, old_offset, citer->offset, len)) {
> > - citer->header = NULL;
> > - } else {
> > - update_new_event(citer);
> > - update_event_size(citer);
> > + buf_access_ops = iter->ltt_channel->buf_access_ops;
> >
> > - if (is_in_region(eof_offset, old_offset,
> > - citer->offset + citer->data_size, len))
> > - citer->header = NULL;
> > + ret = buf_access_ops->get_subbuf(citer->buf, offset);
> > + if (!ret) {
> > + citer->header = ltt_relay_read_offset_address(citer->buf,
> > + *offset);
> > + citer->hdr_offset = (*offset) + ltt_subbuffer_header_size();
> > + citer->tsc = citer->header->cycle_count_begin;
> > + iter->nr_refs++;
> > + citer->sb_ref = 1;
> > + return 0;
> > + } else {
> > + if (buf_access_ops->is_finalized(citer->buf)) {
> > + /*
> > + * Currently, kill the iterator for
> > + * this cpu buffer (TODO resume support)
> > + */
> > + buf_access_ops->release(citer->buf);
> > + citer->buf = NULL;
> > + return -ENODATA;
> > + }
> > + return -EAGAIN;
> > }
> > }
> >
> > -static void start_new_subbuffer(struct ltt_relay_cpu_iter *citer, size_t offset)
> > +static void subbuffer_stop(struct ltt_relay_cpu_iter *citer,
> > + long offset)
> > {
> > - int index = SUBBUF_INDEX(offset, citer->buf->chan);
> > - size_t head_offset = index << citer->buf->chan->subbuf_size_order;
> > + int ret;
> > + struct ltt_relay_iter *iter = citer->iter;
> >
> > - citer->header = ltt_relay_offset_address(citer->buf, head_offset);
> > - citer->offset = head_offset + ltt_subbuffer_header_size();
> > - citer->tsc = citer->header->cycle_count_begin;
> > + WARN_ON_ONCE(!citer->sb_ref);
> > + ret = iter->ltt_channel->buf_access_ops->put_subbuf(
> > + citer->buf, offset);
> > + WARN_ON_ONCE(ret);
> > + citer->sb_ref = 0;
> > + iter->nr_refs--;
> > }
> >
> > static void ltt_relay_advance_cpu_iter(struct ltt_relay_cpu_iter *citer)
> > {
> > - size_t old_offset = citer->offset, new_offset = citer->offset;
> > - size_t sub_offset = SUBBUF_OFFSET(old_offset, citer->buf->chan);
> > -
> > - new_offset += citer->data_size;
> > + long old_offset = citer->payload_offset;
> > + long new_offset = citer->payload_offset;
> > + int ret;
> >
> > /* find that whether we read all data in this subbuffer */
> > - if (sub_offset + citer->data_size + citer->header->lost_size
> > - >= citer->buf->chan->subbuf_size) {
> > - new_offset += citer->header->lost_size;
> > - start_new_subbuffer(citer, new_offset);
> > + if (unlikely(is_subbuffer_offset_end(citer,
> > + old_offset + citer->data_size))) {
> > + DEBUGP(KERN_DEBUG "LTT ASCII stop cpu %d offset %lX\n",
> > + citer->buf->cpu, citer->read_sb_offset);
> > + subbuffer_stop(citer, citer->read_sb_offset);
> > + for (;;) {
> > + ret = subbuffer_start(citer, &citer->read_sb_offset);
> > + DEBUGP(KERN_DEBUG
> > + "LTT ASCII start cpu %d ret %d offset %lX\n",
> > + citer->buf->cpu, ret, citer->read_sb_offset);
> > + if (!ret || ret == -ENODATA) {
> > + break; /* got data, or finalized */
> > + } else { /* -EAGAIN */
> > + if (signal_pending(current))
> > + break;
> > + schedule_timeout_interruptible(1);
> > + }
> > + }
> > } else {
> > - citer->offset = new_offset + ltt_align(new_offset,
> > + new_offset += citer->data_size;
> > + citer->hdr_offset = new_offset + ltt_align(new_offset,
> > sizeof(struct ltt_event_header));
> > + DEBUGP(KERN_DEBUG
> > + "LTT ASCII old_offset %lX new_offset %lX cpu %d\n",
> > + old_offset, new_offset, citer->buf->cpu);
> > }
> >
> > - update_cpu_iter(citer, old_offset);
> > -}
> > -
> > -static void ltt_relay_reset_cpu_iter(struct ltt_relay_cpu_iter *citer)
> > -{
> > - start_new_subbuffer(citer, citer->start_offset);
> > - update_cpu_iter(citer, citer->start_offset);
> > + update_cpu_iter(citer, citer->hdr_offset);
> > }
> >
> > static int cpu_iter_eof(struct ltt_relay_cpu_iter *citer)
> > {
> > - return !citer->header;
> > + return !citer->sb_ref;
> > }
> >
> > -struct ltt_relay_iter {
> > - struct ltt_relay_cpu_iter iter_cpu[NR_CPUS];
> > - struct ltt_channel_struct *ltt_channel;
> > - loff_t pos;
> > - int cpu;
> > -};
> > -
> > static int ltt_relay_iter_eof(struct ltt_relay_iter *iter)
> > {
> > - return iter->cpu < 0;
> > + return iter->nr_refs == 0;
> > }
> >
> > static void ltt_relay_advance_iter(struct ltt_relay_iter *iter)
> > @@ -213,10 +270,10 @@ static void ltt_relay_advance_iter(struc
> > for_each_possible_cpu(i) {
> > curr = &iter->iter_cpu[i];
> >
> > - if (!curr->buf)
> > + if (!curr->buf || !curr->header)
> > continue;
> >
> > - if (cpu_iter_eof(curr) || cpu_iter_empty(curr))
> > + if (cpu_iter_eof(curr))
> > continue;
> >
> > if (!min || curr->tsc < min->tsc) {
> > @@ -228,70 +285,31 @@ static void ltt_relay_advance_iter(struc
> > /* update cpu_iter for next ltt_relay_advance_iter() */
> > if (min)
> > ltt_relay_advance_cpu_iter(min);
> > -
> > - /* increase pos */
> > - iter->pos++;
> > -}
> > -
> > -static void ltt_relay_start_iter(struct ltt_relay_iter *iter)
> > -{
> > - BUG_ON(iter->pos != -1);
> > -
> > - /* TODO: use min-heep for 4096CPUS */
> > - ltt_relay_advance_iter(iter);
> > }
> >
> > static void *ascii_next(struct seq_file *m, void *v, loff_t *ppos)
> > {
> > struct ltt_relay_iter *iter = m->private;
> >
> > - BUG_ON(iter->pos != *ppos || v != iter);
> > + WARN_ON_ONCE(!iter->nr_refs);
> > + BUG_ON(v != iter);
> >
> > ltt_relay_advance_iter(iter);
> > - (*ppos)++;
> > -
> > - return ltt_relay_iter_eof(iter) ? NULL : iter;
> > -}
> > -
> > -/*
> > - * Restart iterator at the beginning of the current subbuffer.
> > - */
> > -static void ltt_relay_reset_iter(struct ltt_relay_iter *iter)
> > -{
> > - int i;
> > -
> > - for_each_possible_cpu(i) {
> > - if (iter->iter_cpu[i].buf)
> > - ltt_relay_reset_cpu_iter(&iter->iter_cpu[i]);
> > - }
> > -
> > - ltt_relay_start_iter(iter);
> > + return (ltt_relay_iter_eof(iter) || signal_pending(current))
> > + ? NULL : iter;
> > }
> >
> > static void *ascii_start(struct seq_file *m, loff_t *ppos)
> > {
> > - loff_t pos = *ppos;
> > struct ltt_relay_iter *iter = m->private;
> >
> > -
> > - if (pos != iter->pos) {
> > - /* restart when read backward */
> > - if (pos < iter->pos)
> > - iter->pos = -1;
> > -
> > - if (iter->pos < 0)
> > - ltt_relay_reset_iter(iter);
> > -
> > - while (!ltt_relay_iter_eof(iter) && iter->pos < pos)
> > - ltt_relay_advance_iter(iter);
> > - }
> > -
> > - return ltt_relay_iter_eof(iter) ? NULL : iter;
> > + ltt_relay_advance_iter(iter);
> > + return (ltt_relay_iter_eof(iter) || signal_pending(current))
> > + ? NULL : iter;
> > }
> >
> > static void ascii_stop(struct seq_file *m, void *v)
> > {
> > - /* do nothing */
> > }
> >
> > static int seq_serialize(struct seq_file *m, struct rchan_buf *buf,
> > @@ -315,22 +333,37 @@ static int seq_serialize(struct seq_file
> > static int ascii_show(struct seq_file *m, void *v)
> > {
> > struct ltt_relay_iter *iter = v;
> > - struct ltt_relay_cpu_iter *citer = &iter->iter_cpu[iter->cpu];
> > + struct ltt_relay_cpu_iter *citer;
> > const char *name;
> > const char *fmt;
> > - unsigned long long tsc = citer->tsc;
> > - size_t *data_size;
> > - data_size = citer->data_size == INT_MAX ? &citer->data_size : NULL;
> > + unsigned long long tsc;
> > + size_t data_size;
> > +
> > + if (iter->cpu == -1)
> > + return 0;
> >
> > - name = marker_get_name_form_id(citer->chID, citer->eID);
> > - fmt = marker_get_fmt_form_id(citer->chID, citer->eID);
> > + citer = &iter->iter_cpu[iter->cpu];
> > + WARN_ON_ONCE(!citer->sb_ref);
> > + /*
> > + * Nothing to show, we are at the end of the last subbuffer currently
> > + * having data.
> > + */
> > + if (!citer->header)
> > + return 0;
> > +
> > + tsc = citer->tsc;
> > + name = marker_get_name_from_id(citer->chID, citer->eID);
> > + fmt = marker_get_fmt_from_id(citer->chID, citer->eID);
> >
> > if (!name || !fmt)
> > return 0;
> >
> > - seq_printf(m, "%16.16s: %2d %20.20llu ", name, iter->cpu, tsc);
> > - seq_serialize(m, citer->buf, citer->offset, fmt, data_size);
> > + seq_printf(m, "event:%16.16s: cpu:%2d time:%20.20llu ",
> > + name, iter->cpu, tsc);
> > + seq_serialize(m, citer->buf, citer->payload_offset, fmt, &data_size);
> > seq_puts(m, "\n");
> > + if (citer->data_size == INT_MAX)
> > + citer->data_size = data_size;
> >
> > return 0;
> > }
> > @@ -342,47 +375,88 @@ static struct seq_operations ascii_seq_o
> > .show = ascii_show,
> > };
> >
> > -#define get_value(ltt_chan, value, cpu) \
> > - ltt_chan->buf_access_ops->get_##value(ltt_chan->buf, cpu)
> > -
> > /* FIXME : cpu hotplug support */
> > -static int ltt_relay_iter_get_channel(struct ltt_relay_iter *iter,
> > +static int ltt_relay_iter_open_channel(struct ltt_relay_iter *iter,
> > struct ltt_channel_struct *ltt_channel)
> > {
> > - int i;
> > + int i, ret;
> > struct rchan *chan = ltt_channel->trans_channel_data;
> > u16 chID = ltt_channels_get_index_from_name(ltt_channel->channel_name);
> > + struct ltt_channel_buf_access_ops *buf_access_ops;
> > +
> > + buf_access_ops = ltt_channel->buf_access_ops;
> >
> > /* we don't need lock relay_channels_mutex */
> > for_each_possible_cpu(i) {
> > - iter->iter_cpu[i].buf = chan->buf[i];
> > - if (iter->iter_cpu[i].buf)
> > - ltt_channel->buf_access_ops->open(ltt_channel->buf, i);
> > - iter->iter_cpu[i].chID = chID;
> > - }
> > -/*
> > - for_each_possible_cpu(i) {
> > - if (!iter->iter_cpu[i].buf)
> > + struct ltt_relay_cpu_iter *citer = &iter->iter_cpu[i];
> > +
> > + citer->buf = chan->buf[i];
> > + if (!citer->buf)
> > continue;
> > - iter->iter_cpu[i].start_offset = SUBBUF_TRUNC(
> > - get_value(ltt_channel, consumed, i),
> > - iter->iter_cpu[i].buf->chan);
> > - iter->iter_cpu[i].eof_offset =
> > - get_value(ltt_channel, offset, i);
> > +
> > + citer->iter = iter; /* easy lazy parent info */
> > + citer->chID = chID;
> > +
> > + ret = buf_access_ops->open(citer->buf);
> > + if (ret) {
> > + /* Failed to open a percpu buffer, close everything. */
> > + citer->buf = NULL;
> > + goto error;
> > + }
> > +
> > + for (;;) {
> > + ret = subbuffer_start(citer,
> > + &citer->read_sb_offset);
> > + DEBUGP(KERN_DEBUG
> > + "LTT ASCII open start "
> > + "cpu %d ret %d offset %lX\n",
> > + citer->buf->cpu, ret, citer->read_sb_offset);
> > + if (!ret || ret == -ENODATA) {
> > + break; /* got data, or finalized */
> > + } else { /* -EAGAIN */
> > + if (signal_pending(current))
> > + break;
> > + schedule_timeout_interruptible(1);
> > + }
> > + }
> > + update_cpu_iter(citer, citer->hdr_offset);
> > }
> > -*/
> > + if (!iter->nr_refs)
> > + return -ENODATA; /* no data available */
> > return 0;
> > +
> > +error:
> > + for_each_possible_cpu(i) {
> > + struct ltt_relay_cpu_iter *citer = &iter->iter_cpu[i];
> > +
> > + if (citer->buf)
> > + buf_access_ops->release(citer->buf);
> > + }
> > + return ret;
> > }
> >
> > -static int ltt_relay_iter_put_channel(struct ltt_relay_iter *iter)
> > +static int ltt_relay_iter_release_channel(struct ltt_relay_iter *iter)
> > {
> > int i;
> > + struct ltt_channel_buf_access_ops *buf_access_ops;
> > +
> > + buf_access_ops = iter->ltt_channel->buf_access_ops;
> >
> > for_each_possible_cpu(i) {
> > - if (iter->iter_cpu[i].buf)
> > - ltt_channel->buf_access_ops->release(ltt_channel->buf,
> > - i);
> > + struct ltt_relay_cpu_iter *citer = &iter->iter_cpu[i];
> > +
> > + if (citer->sb_ref) {
> > + WARN_ON_ONCE(!citer->buf);
> > + DEBUGP(KERN_DEBUG
> > + "LTT ASCII release stop cpu %d offset %lX\n",
> > + citer->buf->cpu, citer->read_sb_offset);
> > + subbuffer_stop(&iter->iter_cpu[i],
> > + citer->read_sb_offset);
> > + }
> > + if (citer->buf)
> > + buf_access_ops->release(citer->buf);
> > }
> > + WARN_ON_ONCE(iter->nr_refs);
> > return 0;
> > }
> >
> > @@ -390,30 +464,34 @@ static int ltt_relay_ascii_open(struct i
> > {
> > int ret;
> > struct ltt_channel_struct *ltt_channel = inode->i_private;
> > - struct ltt_relay_iter *iter = kmalloc(sizeof(*iter), GFP_KERNEL);
> > + struct ltt_relay_iter *iter = kzalloc(sizeof(*iter), GFP_KERNEL);
> > if (!iter)
> > return -ENOMEM;
> >
> > iter->ltt_channel = ltt_channel;
> > - iter->pos = -1;
> > - ltt_relay_iter_get_channel(iter, ltt_channel);
> > + ret = ltt_relay_iter_open_channel(iter, ltt_channel);
> > + if (ret)
> > + goto error_free_alloc;
> >
> > ret = seq_open(file, &ascii_seq_ops);
> > - if (ret) {
> > - ltt_relay_iter_put_channel(iter);
> > - kfree(iter);
> > - return ret;
> > - }
> > + if (ret)
> > + goto error_release_channel;
> > ((struct seq_file *)file->private_data)->private = iter;
> > -
> > return 0;
> > +
> > +error_release_channel:
> > + ltt_relay_iter_release_channel(iter);
> > +error_free_alloc:
> > + kfree(iter);
> > + return ret;
> > }
> >
> > static int ltt_relay_ascii_release(struct inode *inode, struct file *file)
> > {
> > struct seq_file *seq = file->private_data;
> > struct ltt_relay_iter *iter = seq->private;
> > - ltt_relay_iter_put_channel(iter);
> > +
> > + ltt_relay_iter_release_channel(iter);
> > kfree(iter);
> > return 0;
> > }
> > @@ -423,6 +501,7 @@ static struct file_operations ltt_ascii_
> > .read = seq_read,
> > .open = ltt_relay_ascii_open,
> > .release = ltt_relay_ascii_release,
> > + .llseek = no_llseek,
> > .owner = THIS_MODULE,
> > };
> >
> > @@ -433,10 +512,8 @@ struct dentry *ltt_ascii_create(struct l
> > S_IRUSR | S_IRGRP, trace->dentry.ascii_root,
> > ltt_channel,
> > <t_ascii_fops);
> > -
> > if (entry)
> > - ltt_relay_get_chan(ltt_channel->trans_channel_data);
> > -
> > + entry->d_inode->i_private = ltt_channel;
> > return entry;
> > }
> > EXPORT_SYMBOL_GPL(ltt_ascii_create);
> > @@ -444,10 +521,8 @@ EXPORT_SYMBOL_GPL(ltt_ascii_create);
> > void ltt_ascii_remove(struct ltt_channel_struct *ltt_channel,
> > struct dentry *ascii)
> > {
> > - if (ascii) {
> > + if (ascii)
> > debugfs_remove(ascii);
> > - ltt_relay_put_chan(ltt_channel->trans_channel_data);
> > - }
> > }
> > EXPORT_SYMBOL_GPL(ltt_ascii_remove);
> >
> > @@ -470,6 +545,7 @@ EXPORT_SYMBOL_GPL(ltt_ascii_remove_dir);
> > static __init int ltt_ascii_init(void)
> > {
> > ltt_ascii_dir_dentry = debugfs_create_dir(LTT_ASCII, get_ltt_root());
> > + put_ltt_root();
> >
> > return ltt_ascii_dir_dentry ? 0 : -EFAULT;
> > }
> > Index: linux-2.6-lttng/include/linux/ltt-relay.h
> > ===================================================================
> > --- linux-2.6-lttng.orig/include/linux/ltt-relay.h 2009-07-20 09:27:28.000000000 -0400
> > +++ linux-2.6-lttng/include/linux/ltt-relay.h 2009-07-20 09:27:28.000000000 -0400
> > @@ -60,6 +60,7 @@ struct rchan_buf {
> > unsigned int page_count; /* number of current buffer pages */
> > unsigned int cpu; /* this buf's cpu */
> > unsigned int random_access; /* buffer performs random page access */
> > + struct dentry *ascii_dentry; /* Text output dentry */
> > } ____cacheline_aligned;
> >
> > /*
> > @@ -167,6 +168,8 @@ extern struct page *ltt_relay_read_get_p
> > */
> > extern void *ltt_relay_offset_address(struct rchan_buf *buf,
> > size_t offset);
> > +extern void *ltt_relay_read_offset_address(struct rchan_buf *buf,
> > + size_t offset);
> >
> > #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
> > static __inline__ void ltt_relay_do_copy(void *dest, const void *src, size_t len)
> > Index: linux-2.6-lttng/ltt/ltt-relay-alloc.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/ltt-relay-alloc.c 2009-07-20 09:27:28.000000000 -0400
> > +++ linux-2.6-lttng/ltt/ltt-relay-alloc.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -631,9 +631,11 @@ int ltt_relay_read_cstr(struct rchan_buf
> > strpagelen = strnlen(str, pagelen);
> > if (len) {
> > pagecpy = min_t(size_t, len, strpagelen);
> > - memcpy(dest, str, pagecpy);
> > + if (dest) {
> > + memcpy(dest, str, pagecpy);
> > + dest += pagecpy;
> > + }
> > len -= pagecpy;
> > - dest += pagecpy;
> > }
> > offset += strpagelen;
> > index = (offset & (buf->chan->subbuf_size - 1)) >> PAGE_SHIFT;
> > @@ -645,7 +647,7 @@ int ltt_relay_read_cstr(struct rchan_buf
> > */
> > WARN_ON(offset >= buf->chan->alloc_size);
> > }
> > - if (len)
> > + if (dest && len)
> > ((char *)dest)[0] = 0;
> > return offset - orig_offset;
> > }
> > Index: linux-2.6-lttng/include/linux/ltt-channels.h
> > ===================================================================
> > --- linux-2.6-lttng.orig/include/linux/ltt-channels.h 2009-07-20 09:27:26.000000000 -0400
> > +++ linux-2.6-lttng/include/linux/ltt-channels.h 2009-07-20 09:27:28.000000000 -0400
> > @@ -20,7 +20,6 @@ struct rchan_buf;
> > struct ltt_channel_struct {
> > /* First 32 bytes cache-hot cacheline */
> > struct ltt_trace_struct *trace;
> > - void *buf;
> > void *trans_channel_data;
> > int overwrite:1;
> > int active:1;
> > @@ -53,6 +52,7 @@ struct ltt_channel_buf_access_ops {
> > int (*release)(struct rchan_buf *buf);
> > int (*get_subbuf)(struct rchan_buf *buf, unsigned long *consumed);
> > int (*put_subbuf)(struct rchan_buf *buf, unsigned long consumed);
> > + int (*is_finalized)(struct rchan_buf *buf);
> > unsigned long (*get_n_subbufs)(struct rchan_buf *buf);
> > unsigned long (*get_subbuf_size)(struct rchan_buf *buf);
> > void (*start_switch_timer)(struct ltt_channel_struct *ltt_channel);
> > Index: linux-2.6-lttng/ltt/ltt-relay-irqoff.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/ltt-relay-irqoff.c 2009-07-20 09:27:28.000000000 -0400
> > +++ linux-2.6-lttng/ltt/ltt-relay-irqoff.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -136,6 +136,8 @@ static struct dentry *ltt_create_buf_fil
> > <t_file_operations);
> > if (!dentry)
> > goto error;
> > + if (buf->cpu == 0)
> > + buf->ascii_dentry = ltt_ascii_create(ltt_chan->trace, ltt_chan);
> > return dentry;
> > error:
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> > @@ -147,6 +149,7 @@ static int ltt_remove_buf_file_callback(
> > struct rchan_buf *buf = dentry->d_inode->i_private;
> > struct ltt_channel_struct *ltt_chan = buf->chan->private_data;
> >
> > + ltt_ascii_remove(ltt_chan, buf->ascii_dentry);
> > debugfs_remove(dentry);
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> >
> > @@ -213,6 +216,13 @@ static int _ltt_release(struct rchan_buf
> > return 0;
> > }
> >
> > +static int is_finalized(struct rchan_buf *buf)
> > +{
> > + struct ltt_channel_buf_struct *ltt_buf = buf->chan_private;
> > +
> > + return ltt_buf->finalized;
> > +}
> > +
> > /*
> > * Promote compiler barrier to a smp_mb().
> > * For the specific LTTng case, this IPI call should be removed if the
> > @@ -443,6 +453,7 @@ static struct ltt_channel_buf_access_ops
> > .get_consumed = get_consumed,
> > .get_subbuf = get_subbuf,
> > .put_subbuf = put_subbuf,
> > + .is_finalized = is_finalized,
> > .get_n_subbufs = get_n_subbufs,
> > .get_subbuf_size = get_subbuf_size,
> > .open = _ltt_open,
> > @@ -828,6 +839,7 @@ static void ltt_relay_print_buffer_error
> >
> > static void ltt_relay_remove_dirs(struct ltt_trace_struct *trace)
> > {
> > + ltt_ascii_remove_dir(trace);
> > debugfs_remove(trace->dentry.trace_root);
> > }
> >
> > @@ -974,6 +986,7 @@ end:
> > static int ltt_relay_create_dirs(struct ltt_trace_struct *new_trace)
> > {
> > struct dentry *ltt_root_dentry;
> > + int ret;
> >
> > ltt_root_dentry = get_ltt_root();
> > if (!ltt_root_dentry)
> > @@ -987,6 +1000,10 @@ static int ltt_relay_create_dirs(struct
> > new_trace->trace_name);
> > return EEXIST;
> > }
> > + ret = ltt_ascii_create_dir(new_trace);
> > + if (ret)
> > + printk(KERN_WARNING "LTT : Unable to create ascii output file "
> > + "for trace %s\n", new_trace->trace_name);
> >
> > new_trace->callbacks.create_buf_file = ltt_create_buf_file_callback;
> > new_trace->callbacks.remove_buf_file = ltt_remove_buf_file_callback;
> > Index: linux-2.6-lttng/ltt/ltt-relay-lockless.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/ltt-relay-lockless.c 2009-07-20 09:27:28.000000000 -0400
> > +++ linux-2.6-lttng/ltt/ltt-relay-lockless.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -137,6 +137,8 @@ static struct dentry *ltt_create_buf_fil
> > <t_file_operations);
> > if (!dentry)
> > goto error;
> > + if (buf->cpu == 0)
> > + buf->ascii_dentry = ltt_ascii_create(ltt_chan->trace, ltt_chan);
> > return dentry;
> > error:
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> > @@ -148,6 +150,7 @@ static int ltt_remove_buf_file_callback(
> > struct rchan_buf *buf = dentry->d_inode->i_private;
> > struct ltt_channel_struct *ltt_chan = buf->chan->private_data;
> >
> > + ltt_ascii_remove(ltt_chan, buf->ascii_dentry);
> > debugfs_remove(dentry);
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> >
> > @@ -214,6 +217,13 @@ static int _ltt_release(struct rchan_buf
> > return 0;
> > }
> >
> > +static int is_finalized(struct rchan_buf *buf)
> > +{
> > + struct ltt_channel_buf_struct *ltt_buf = buf->chan_private;
> > +
> > + return ltt_buf->finalized;
> > +}
> > +
> > /*
> > * Promote compiler barrier to a smp_mb().
> > * For the specific LTTng case, this IPI call should be removed if the
> > @@ -444,6 +454,7 @@ static struct ltt_channel_buf_access_ops
> > .get_consumed = get_consumed,
> > .get_subbuf = get_subbuf,
> > .put_subbuf = put_subbuf,
> > + .is_finalized = is_finalized,
> > .get_n_subbufs = get_n_subbufs,
> > .get_subbuf_size = get_subbuf_size,
> > .open = _ltt_open,
> > @@ -831,6 +842,7 @@ static void ltt_relay_print_buffer_error
> >
> > static void ltt_relay_remove_dirs(struct ltt_trace_struct *trace)
> > {
> > + ltt_ascii_remove_dir(trace);
> > debugfs_remove(trace->dentry.trace_root);
> > }
> >
> > @@ -979,6 +991,7 @@ end:
> > static int ltt_relay_create_dirs(struct ltt_trace_struct *new_trace)
> > {
> > struct dentry *ltt_root_dentry;
> > + int ret;
> >
> > ltt_root_dentry = get_ltt_root();
> > if (!ltt_root_dentry)
> > @@ -992,6 +1005,10 @@ static int ltt_relay_create_dirs(struct
> > new_trace->trace_name);
> > return EEXIST;
> > }
> > + ret = ltt_ascii_create_dir(new_trace);
> > + if (ret)
> > + printk(KERN_WARNING "LTT : Unable to create ascii output file "
> > + "for trace %s\n", new_trace->trace_name);
> >
> > new_trace->callbacks.create_buf_file = ltt_create_buf_file_callback;
> > new_trace->callbacks.remove_buf_file = ltt_remove_buf_file_callback;
> > Index: linux-2.6-lttng/ltt/ltt-relay-locked.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/ltt-relay-locked.c 2009-07-20 09:27:28.000000000 -0400
> > +++ linux-2.6-lttng/ltt/ltt-relay-locked.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -137,6 +137,8 @@ static struct dentry *ltt_create_buf_fil
> > <t_file_operations);
> > if (!dentry)
> > goto error;
> > + if (buf->cpu == 0)
> > + buf->ascii_dentry = ltt_ascii_create(ltt_chan->trace, ltt_chan);
> > return dentry;
> > error:
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> > @@ -148,6 +150,7 @@ static int ltt_remove_buf_file_callback(
> > struct rchan_buf *buf = dentry->d_inode->i_private;
> > struct ltt_channel_struct *ltt_chan = buf->chan->private_data;
> >
> > + ltt_ascii_remove(ltt_chan, buf->ascii_dentry);
> > debugfs_remove(dentry);
> > ltt_relay_destroy_buffer(ltt_chan, buf->cpu);
> >
> > @@ -214,6 +217,13 @@ static int _ltt_release(struct rchan_buf
> > return 0;
> > }
> >
> > +static int is_finalized(struct rchan_buf *buf)
> > +{
> > + struct ltt_channel_buf_struct *ltt_buf = buf->chan_private;
> > +
> > + return ltt_buf->finalized;
> > +}
> > +
> > static int get_subbuf(struct rchan_buf *buf, unsigned long *consumed)
> > {
> > struct ltt_channel_struct *ltt_channel =
> > @@ -396,6 +406,7 @@ static struct ltt_channel_buf_access_ops
> > .get_consumed = get_consumed,
> > .get_subbuf = get_subbuf,
> > .put_subbuf = put_subbuf,
> > + .is_finalized = is_finalized,
> > .get_n_subbufs = get_n_subbufs,
> > .get_subbuf_size = get_subbuf_size,
> > .open = _ltt_open,
> > @@ -783,6 +794,7 @@ static void ltt_relay_print_buffer_error
> >
> > static void ltt_relay_remove_dirs(struct ltt_trace_struct *trace)
> > {
> > + ltt_ascii_remove_dir(trace);
> > debugfs_remove(trace->dentry.trace_root);
> > }
> >
> > @@ -918,6 +930,7 @@ end:
> > static int ltt_relay_create_dirs(struct ltt_trace_struct *new_trace)
> > {
> > struct dentry *ltt_root_dentry;
> > + int ret;
> >
> > ltt_root_dentry = get_ltt_root();
> > if (!ltt_root_dentry)
> > @@ -931,6 +944,10 @@ static int ltt_relay_create_dirs(struct
> > new_trace->trace_name);
> > return EEXIST;
> > }
> > + ret = ltt_ascii_create_dir(new_trace);
> > + if (ret)
> > + printk(KERN_WARNING "LTT : Unable to create ascii output file "
> > + "for trace %s\n", new_trace->trace_name);
> >
> > new_trace->callbacks.create_buf_file = ltt_create_buf_file_callback;
> > new_trace->callbacks.remove_buf_file = ltt_remove_buf_file_callback;
> > Index: linux-2.6-lttng/kernel/marker.c
> > ===================================================================
> > --- linux-2.6-lttng.orig/kernel/marker.c 2009-07-20 09:27:27.000000000 -0400
> > +++ linux-2.6-lttng/kernel/marker.c 2009-07-20 09:27:28.000000000 -0400
> > @@ -1107,19 +1107,19 @@ static struct marker_entry *get_entry_fr
> > }
> >
> > /* must call when ids/marker_entry are kept alive */
> > -const char *marker_get_name_form_id(u16 channel_id, u16 event_id)
> > +const char *marker_get_name_from_id(u16 channel_id, u16 event_id)
> > {
> > struct marker_entry *e = get_entry_from_id(channel_id, event_id);
> > return e ? e->name : NULL;
> > }
> > -EXPORT_SYMBOL_GPL(marker_get_name_form_id);
> > +EXPORT_SYMBOL_GPL(marker_get_name_from_id);
> >
> > -const char *marker_get_fmt_form_id(u16 channel_id, u16 event_id)
> > +const char *marker_get_fmt_from_id(u16 channel_id, u16 event_id)
> > {
> > struct marker_entry *e = get_entry_from_id(channel_id, event_id);
> > return e ? e->format : NULL;
> > }
> > -EXPORT_SYMBOL_GPL(marker_get_fmt_form_id);
> > +EXPORT_SYMBOL_GPL(marker_get_fmt_from_id);
> >
> > /**
> > * markers_compact_event_ids - Compact markers event IDs and reassign channels
> > Index: linux-2.6-lttng/include/linux/ltt-tracer.h
> > ===================================================================
> > --- linux-2.6-lttng.orig/include/linux/ltt-tracer.h 2009-07-20 09:27:27.000000000 -0400
> > +++ linux-2.6-lttng/include/linux/ltt-tracer.h 2009-07-20 09:27:28.000000000 -0400
> > @@ -654,6 +654,35 @@ extern void ltt_dump_marker_state(struct
> > void ltt_lock_traces(void);
> > void ltt_unlock_traces(void);
> >
> > +#ifdef CONFIG_LTT_ASCII
> > +extern int ltt_ascii_create_dir(struct ltt_trace_struct *new_trace);
> > +extern void ltt_ascii_remove_dir(struct ltt_trace_struct *trace);
> > +extern struct dentry *ltt_ascii_create(struct ltt_trace_struct *trace,
> > + struct ltt_channel_struct *ltt_channel);
> > +extern void ltt_ascii_remove(struct ltt_channel_struct *ltt_channel,
> > + struct dentry *ascii);
> > +#else
> > +static inline int ltt_ascii_create_dir(struct ltt_trace_struct *new_trace)
> > +{
> > + return 0;
> > +}
> > +
> > +static inline void ltt_ascii_remove_dir(struct ltt_trace_struct *trace)
> > +{
> > +}
> > +
> > +static inline struct dentry *ltt_ascii_create(struct ltt_trace_struct *trace,
> > + struct ltt_channel_struct *ltt_channel)
> > +{
> > + return NULL;
> > +}
> > +
> > +static inline void ltt_ascii_remove(struct ltt_channel_struct *ltt_channel,
> > + struct dentry *ascii)
> > +{
> > +}
> > +#endif
> > +
> > extern void ltt_statedump_register_kprobes_dump(
> > void (*callback)(void *call_data));
> > extern void ltt_statedump_unregister_kprobes_dump(
> > Index: linux-2.6-lttng/Documentation/lttng.txt
> > ===================================================================
> > --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> > +++ linux-2.6-lttng/Documentation/lttng.txt 2009-07-20 09:27:28.000000000 -0400
> > @@ -0,0 +1,35 @@
> > +
> > +Linux Text Toolkit Next Generation
> > +Mathieu Desnoyers, July 2009
> > +
> > +This guide contains quickstart information on how to to use LTTng. It currently
> > +only contains information about ascii text dump, but (TODO) we should bring the
> > +LTTng manual here.
> > +
> > + * Quick and dirty startup ascii output script:
> > +
> > +#!/bin/sh
> > +
> > +LTT_DIR=/mnt/debugfs/ltt
> > +ltt-armall
> > +echo trace > ${LTT_DIR}/setup_trace
> > +cd control/
> > +cd trace/
> > +echo relay > ${LTT_DIR}/control/trace/trans
> > +cd channel/
> > +for a in ${LTT_DIR}/control/trace/channel/*/switch_timer;
> > + do echo 100 > $a; done
> > +#note: error for metadata channel for the following line is OK
> > +#it is not permitted to set metadata channel in overwrite mode
> > +for a in ${LTT_DIR}/control/trace/channel/*/overwrite;
> > + do echo 1 > $a; done
> > +for a in ${LTT_DIR}/control/trace/channel/*/enable;
> > + do echo 1 > $a; done
> > +cd ..
> > +echo 1 > ${LTT_DIR}/control/trace/alloc
> > +echo 1 > ${LTT_DIR}/control/trace/enabled
> > +
> > +To see the events for a given channel (e.g. kernel events):
> > +
> > +cat ${LTT_DIR}/ascii/trace/kernel
> > +(hit CTRL-C to stop)
> > Index: linux-2.6-lttng/ltt/Kconfig
> > ===================================================================
> > --- linux-2.6-lttng.orig/ltt/Kconfig 2009-07-20 09:27:54.000000000 -0400
> > +++ linux-2.6-lttng/ltt/Kconfig 2009-07-20 09:29:10.000000000 -0400
> > @@ -208,7 +208,8 @@ config LTT_FTRACE
> > surroundings of a problem has been identified in a prior trace.
> >
> > config LTT_ASCII
> > - bool "Linux Trace Toolkit Ascii Output (work in progress)"
> > + bool "Linux Trace Toolkit Ascii Output (EXPERIMENTAL)"
> > + depends on EXPERIMENTAL
> > depends on LTT_TRACER
> > depends on LTT_RELAY_ALLOC
> > depends on LTT_SERIALIZE
> >
> >
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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