Re: [ltt-dev] LTTng 0.149 adds experimental ascii output module

From: Benjamin Poirier
Date: Mon Jul 20 2009 - 14:40:38 EST

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 ‘cpufreq_add_dev’:
drivers/cpufreq/cpufreq.c:957: error: ‘managed_policy’ 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 ‘err_unlock_gov_mutex’
defined but not used
make[2]: *** [drivers/cpufreq/cpufreq.o] Error 1

-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,
> &ltt_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
> &ltt_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
> &ltt_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
> &ltt_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
>
>
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