From: Nicholas Bellinger <nab@xxxxxxxxxxxxx>
This patch introduces two counters for ABORT_TASK success +
failure under:
/sys/kernel/config/target/core/$HBA/$DEV/statistics/scsi_tgt_dev/
that are useful for diagnosing various backend device latency
and front fabric issues.
Normally when folks see alot of aborts_complete happening,
it means the backend device I/O completion latency is high,
and not returning completions fast enough before host side
timeouts trigger.
And normally when folks see alot of aborts_no_task, it means
completions are being posted by target-core into fabric driver
code, but the responses aren't making it back to the host.
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_stat.c | 18 ++++++++++++++++++
drivers/target/target_core_tmr.c | 2 ++
include/target/target_core_base.h | 2 ++
3 files changed, 22 insertions(+)
diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index be380e4..8038255 100644
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -158,12 +158,28 @@ static ssize_t target_stat_tgt_resets_show(struct config_item *item,
atomic_long_read(&to_stat_tgt_dev(item)->num_resets));
}
+static ssize_t target_stat_tgt_aborts_complete_show(struct config_item *item,
+ char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%lu\n",
+ atomic_long_read(&to_stat_tgt_dev(item)->aborts_complete));
+}
+
+static ssize_t target_stat_tgt_aborts_no_task_show(struct config_item *item,
+ char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%lu\n",
+ atomic_long_read(&to_stat_tgt_dev(item)->aborts_no_task));
+}
+
CONFIGFS_ATTR_RO(target_stat_tgt_, inst);
CONFIGFS_ATTR_RO(target_stat_tgt_, indx);
CONFIGFS_ATTR_RO(target_stat_tgt_, num_lus);
CONFIGFS_ATTR_RO(target_stat_tgt_, status);
CONFIGFS_ATTR_RO(target_stat_tgt_, non_access_lus);
CONFIGFS_ATTR_RO(target_stat_tgt_, resets);
+CONFIGFS_ATTR_RO(target_stat_tgt_, aborts_complete);
+CONFIGFS_ATTR_RO(target_stat_tgt_, aborts_no_task);
static struct configfs_attribute *target_stat_scsi_tgt_dev_attrs[] = {
&target_stat_tgt_attr_inst,
@@ -172,6 +188,8 @@ static ssize_t target_stat_tgt_resets_show(struct config_item *item,
&target_stat_tgt_attr_status,
&target_stat_tgt_attr_non_access_lus,
&target_stat_tgt_attr_resets,
+ &target_stat_tgt_attr_aborts_complete,
+ &target_stat_tgt_attr_aborts_no_task,
NULL,
};
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index a806d9b..dce1e1b 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -190,6 +190,7 @@ void core_tmr_abort_task(
printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
" ref_tag: %llu\n", ref_tag);
tmr->response = TMR_FUNCTION_COMPLETE;
+ atomic_long_inc(&dev->aborts_complete);
return;
}
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
@@ -197,6 +198,7 @@ void core_tmr_abort_task(
printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
tmr->ref_task_tag);
tmr->response = TMR_TASK_DOES_NOT_EXIST;
+ atomic_long_inc(&dev->aborts_no_task);
}
static void core_tmr_drain_tmr_list(
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 16d3be8..49ce5bc 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -766,6 +766,8 @@ struct se_device {
u32 dev_index;
u64 creation_time;
atomic_long_t num_resets;
+ atomic_long_t aborts_complete;
+ atomic_long_t aborts_no_task;
atomic_long_t num_cmds;
atomic_long_t read_bytes;
atomic_long_t write_bytes;
--
1.9.1
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