[Patch] zfcp: gather HBA-specific latencies in statistics
From: Martin Peschke
Date: Fri Aug 18 2006 - 07:42:41 EST
This patch requires the <linux/statistic.h> API, and applies to
2.6.18-rc4-mm1.
Newer versions of the System z FCP HBA (s390 arch) provide additional
measurement data, including a so called 'channel latency' (roughly the
time a request spent in the HBA) and a 'fabric latency' (the time a
request spent outside the System z machine).
This patch allows users to accumulate these latencies - separately for
requests with outbound/inbound/no data transfer - in statistics, that
is, histograms by default. These statistics are useful when there is a
need to further break down overall latencies as seen by Linux.
Signed-off-by: Martin Peschke <mp3@xxxxxxxxxx>
Acked-by: Andreas Herrmann <aherrman@xxxxxxxxxx>
---
zfcp_aux.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
zfcp_def.h | 13 +++++++++++++
zfcp_fsf.c | 38 ++++++++++++++++++++++++++++++++++++++
zfcp_fsf.h | 12 +++++++++++-
4 files changed, 117 insertions(+), 1 deletion(-)
diff -ur a/drivers/s390/scsi/zfcp_fsf.h b/drivers/s390/scsi/zfcp_fsf.h
--- a/drivers/s390/scsi/zfcp_fsf.h 2006-08-18 12:31:09.000000000 +0200
+++ b/drivers/s390/scsi/zfcp_fsf.h 2006-08-18 12:32:59.000000000 +0200
@@ -213,6 +213,7 @@
#define FSF_FEATURE_HBAAPI_MANAGEMENT 0x00000010
#define FSF_FEATURE_ELS_CT_CHAINED_SBALS 0x00000020
#define FSF_FEATURE_UPDATE_ALERT 0x00000100
+#define FSF_FEATURE_MEASUREMENT_DATA 0x00000200
/* host connection features */
#define FSF_FEATURE_NPIV_MODE 0x00000001
@@ -322,11 +323,18 @@
u8 vendor_specific_code;
} __attribute__ ((packed));
+struct fsf_measurement_data {
+ u32 channel_latency;
+ u32 fabric_latency;
+ u8 res1[8];
+} __attribute__ ((packed));
+
union fsf_prot_status_qual {
u64 doubleword[FSF_PROT_STATUS_QUAL_SIZE / sizeof(u64)];
struct fsf_qual_version_error version_error;
struct fsf_qual_sequence_error sequence_error;
struct fsf_link_down_info link_down_info;
+ struct fsf_measurement_data measurement_data;
} __attribute__ ((packed));
struct fsf_qtcb_prefix {
@@ -427,7 +435,9 @@
u32 fc_link_speed;
u32 adapter_type;
u32 peer_d_id;
- u8 res2[12];
+ u16 status_read_buf_num;
+ u16 timer_tick_interval;
+ u8 res2[8];
u32 s_id;
struct fsf_nport_serv_param nport_serv_param;
u8 reserved_nport_serv_param[16];
diff -ur a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h
--- a/drivers/s390/scsi/zfcp_def.h 2006-08-18 12:31:26.000000000 +0200
+++ b/drivers/s390/scsi/zfcp_def.h 2006-08-18 12:32:59.000000000 +0200
@@ -889,6 +889,7 @@
u32 adapter_features; /* FCP channel features */
u32 connection_features; /* host connection features */
u32 hardware_version; /* of FCP channel */
+ u16 timer_tick_interval; /* for measurement data */
struct Scsi_Host *scsi_host; /* Pointer to mid-layer */
struct list_head port_list_head; /* remote port list */
struct list_head port_remove_lh; /* head of ports to be
@@ -973,6 +974,16 @@
u32 supported_classes;
};
+enum zfcp_unit_stats {
+ ZFCP_STAT_U_CLW,
+ ZFCP_STAT_U_CLR,
+ ZFCP_STAT_U_CLN,
+ ZFCP_STAT_U_FLW,
+ ZFCP_STAT_U_FLR,
+ ZFCP_STAT_U_FLN,
+ _ZFCP_STAT_U_NUMBER,
+};
+
/* the struct device sysfs_device must be at the beginning of this structure.
* pointer to struct device is used to free unit structure in release function
* of the device. don't change!
@@ -991,6 +1002,8 @@
struct scsi_device *device; /* scsi device struct pointer */
struct zfcp_erp_action erp_action; /* pending error recovery */
atomic_t erp_counter;
+ struct statistic_interface stat_if;
+ struct statistic stat[_ZFCP_STAT_U_NUMBER];
};
/* FSF request */
diff -ur a/drivers/s390/scsi/zfcp_aux.c b/drivers/s390/scsi/zfcp_aux.c
--- a/drivers/s390/scsi/zfcp_aux.c 2006-08-18 12:31:26.000000000 +0200
+++ b/drivers/s390/scsi/zfcp_aux.c 2006-08-18 12:32:59.000000000 +0200
@@ -826,6 +826,51 @@
return found ? adapter : NULL;
}
+static struct statistic_info zfcp_statinfo_u[] = {
+ [ZFCP_STAT_U_CLW] = {
+ .name = "channel_latency_write",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=17 "
+ "base_interval=1000 range_min=0"
+ },
+ [ZFCP_STAT_U_CLR] = {
+ .name = "channel_latency_read",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=17 "
+ "base_interval=1000 range_min=0"
+ },
+ [ZFCP_STAT_U_CLN] = {
+ .name = "channel_latency_nodata",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=17 "
+ "base_interval=1000 range_min=0"
+ },
+ [ZFCP_STAT_U_FLW] = {
+ .name = "fabric_latency_write",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=13 "
+ "base_interval=1000000 range_min=0"
+ },
+ [ZFCP_STAT_U_FLR] = {
+ .name = "fabric_latency_read",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=13 "
+ "base_interval=1000000 range_min=0"
+ },
+ [ZFCP_STAT_U_FLN] = {
+ .name = "fabric_latency_nodata",
+ .x_unit = "nanosec",
+ .y_unit = "request",
+ .defaults = "type=histogram_log2 entries=13 "
+ "base_interval=1000000 range_min=0"
+ }
+};
+
/**
* zfcp_unit_enqueue - enqueue unit to unit list of a port.
* @port: pointer to port where unit is added
@@ -841,6 +886,7 @@
struct zfcp_unit *unit, *tmp_unit;
unsigned int scsi_lun;
int found;
+ char name[64];
/*
* check that there is no unit with this FCP_LUN already in list
@@ -873,6 +919,14 @@
/* mark unit unusable as long as sysfs registration is not complete */
atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
+ sprintf(name, "zfcp-%s-0x%016Lx-0x%016Lx",
+ zfcp_get_busid_by_unit(unit), port->wwpn, fcp_lun);
+ unit->stat_if.stat = unit->stat;
+ unit->stat_if.info = zfcp_statinfo_u;
+ unit->stat_if.number = _ZFCP_STAT_U_NUMBER;
+ if (statistic_create(&unit->stat_if, name))
+ printk("statistics are unavailable (%s)\n", name);
+
if (device_register(&unit->sysfs_device)) {
kfree(unit);
return NULL;
@@ -919,6 +973,7 @@
write_unlock_irq(&zfcp_data.config_lock);
unit->port->units--;
zfcp_port_put(unit->port);
+ statistic_remove(&unit->stat_if);
zfcp_sysfs_unit_remove_files(&unit->sysfs_device);
device_unregister(&unit->sysfs_device);
}
diff -ur a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c
--- a/drivers/s390/scsi/zfcp_fsf.c 2006-08-18 12:31:26.000000000 +0200
+++ b/drivers/s390/scsi/zfcp_fsf.c 2006-08-18 12:32:59.000000000 +0200
@@ -2017,6 +2017,7 @@
adapter->fsf_lic_version = bottom->lic_version;
adapter->adapter_features = bottom->adapter_features;
adapter->connection_features = bottom->connection_features;
+ adapter->timer_tick_interval = bottom->timer_tick_interval;
adapter->peer_wwpn = 0;
adapter->peer_wwnn = 0;
adapter->peer_d_id = 0;
@@ -3983,6 +3984,38 @@
return retval;
}
+#ifdef CONFIG_STATISTICS
+static void zfcp_fsf_sfc_stat(struct zfcp_fsf_req *fsf_req,
+ struct scsi_cmnd *cmd)
+{
+ struct zfcp_adapter *adapter = fsf_req->unit->port->adapter;
+ struct statistic *stat = fsf_req->unit->stat;
+ struct fsf_measurement_data *data;
+ s64 channel_latency, fabric_latency;
+ unsigned long flags;
+
+ if (!(adapter->adapter_features & FSF_FEATURE_MEASUREMENT_DATA))
+ return;
+
+ data = &fsf_req->qtcb->prefix.prot_status_qual.measurement_data;
+ channel_latency = data->channel_latency * adapter->timer_tick_interval;
+ fabric_latency = data->fabric_latency * adapter->timer_tick_interval;
+
+ local_irq_save(flags);
+ if (cmd->sc_data_direction == DMA_TO_DEVICE) {
+ _statistic_inc(stat, ZFCP_STAT_U_CLW, channel_latency);
+ _statistic_inc(stat, ZFCP_STAT_U_FLW, fabric_latency);
+ } else if (cmd->sc_data_direction == DMA_FROM_DEVICE) {
+ _statistic_inc(stat, ZFCP_STAT_U_CLR, channel_latency);
+ _statistic_inc(stat, ZFCP_STAT_U_FLR, fabric_latency);
+ } else if (cmd->sc_data_direction == DMA_NONE) {
+ _statistic_inc(stat, ZFCP_STAT_U_CLN, channel_latency);
+ _statistic_inc(stat, ZFCP_STAT_U_FLN, fabric_latency);
+ }
+ local_irq_restore(flags);
+}
+#endif
+
/*
* function: zfcp_fsf_send_fcp_command_task_handler
*
@@ -4051,6 +4084,11 @@
fcp_rsp_iu->fcp_sns_len);
}
+ /* we get hba measurement data regardless of the scsi status */
+#ifdef CONFIG_STATISTICS
+ zfcp_fsf_sfc_stat(fsf_req, scpnt);
+#endif
+
/* check FCP_RSP_INFO */
if (unlikely(fcp_rsp_iu->validity.bits.fcp_rsp_len_valid)) {
ZFCP_LOG_DEBUG("rsp_len is valid\n");
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/