[Devel] [PATCH 3/3] target: add histogram for LUN statistics
Andrey Grafin
Andrey.Grafin at acronis.com
Wed Dec 13 16:10:16 MSK 2017
This patch adds histogram statistics to scsi_ports_stats.
Histogram can be obtained and configured via config_fs.
Histogram measurement unit is usec.
Histogram usage:
1. Configure histogram '| 1 ms | 10 ms | 15 ms | largest values |'
`echo "1000 10000 15000" > target/iscsi/iqn.2003-01.org.linux-iscsi.localhost.x8664\:sn.fdee138936b9/tpgt_1/lun/lun_3/statistics/scsi_tgt_port/write_hist`
2. Obtain histogram stats
`cat /target/iscsi/iqn.2003-01.org.linux-iscsi.localhost.x8664\:sn.fdee138936b9/tpgt_1/lun/lun_3/statistics/scsi_tgt_port/write_hist`
3. Stop histogram stats
`echo "" > /target/iscsi/iqn.2003-01.org.linux-iscsi.localhost.x8664\:sn.fdee138936b9/tpgt_1/lun/lun_3/statistics/scsi_tgt_port/write_hist`
Signed-off-by: Andrey Grafin <Andrey.Grafin at acronis.com>
---
drivers/target/target_core_stat.c | 207 +++++++++++++++++++++++++++++++++
drivers/target/target_core_tpg.c | 27 +++++
drivers/target/target_core_transport.c | 23 ++++
include/target/target_core_base.h | 16 +++
4 files changed, 273 insertions(+)
diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c
index e88e29612db..6445869a22b 100644
--- a/drivers/target/target_core_stat.c
+++ b/drivers/target/target_core_stat.c
@@ -33,6 +33,7 @@
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/configfs.h>
+#include <linux/ctype.h>
#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
@@ -699,6 +700,209 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_##_name( \
return ret; \
}
+#define DEV_STAT_SCSI_TGT_PORT_SHOW_HIST(_name) \
+static ssize_t target_stat_scsi_tgt_port_show_attr_##_name( \
+ struct se_port_stat_grps *pgrps, char *page) \
+{ \
+ ssize_t size = -ENODEV; \
+ struct se_lun *lun = container_of(pgrps, \
+ struct se_lun, port_stat_grps); \
+ \
+ spin_lock(&lun->lun_sep_lock); \
+ if (lun->lun_sep) { \
+ rcu_read_lock(); \
+ size = snprintf_histogram(page, PAGE_SIZE, \
+ rcu_dereference(lun->lun_stats._name)); \
+ rcu_read_unlock(); \
+ } \
+ spin_unlock(&lun->lun_sep_lock); \
+ return size; \
+}
+
+#define DEV_STAT_SCSI_TGT_PORT_STORE_HIST(_name) \
+static ssize_t target_stat_scsi_tgt_port_store_attr_##_name( \
+ struct se_port_stat_grps *pgrps, const char *page, size_t size) \
+{ \
+ struct se_lun *lun = container_of(pgrps, \
+ struct se_lun, port_stat_grps); \
+ struct scsi_port_stats_hist *old, *new; \
+ ssize_t ret; \
+ \
+ new = kzalloc(sizeof(*new), GFP_KERNEL); \
+ if (!new) \
+ return -ENOMEM; \
+ \
+ ret = read_histogram_items(page, \
+ size, new->items, TCM_SE_PORT_STATS_HIST_MAX - 1); \
+ \
+ if (ret < 0) \
+ goto err; \
+ \
+ if (ret == 0) { \
+ kfree(new); \
+ new = NULL; \
+ } else { \
+ new->items[ret] = U64_MAX; \
+ new->count = ret + 1; \
+ } \
+ \
+ spin_lock(&lun->lun_sep_lock); \
+ \
+ if (!lun->lun_sep) { \
+ spin_unlock(&lun->lun_sep_lock); \
+ ret = -ENODEV; \
+ goto err; \
+ } \
+ \
+ old = rcu_dereference_protected(lun->lun_stats._name, \
+ lockdep_is_held(&lun->lun_sep_lock)); \
+ rcu_assign_pointer(lun->lun_stats._name, new); \
+ \
+ spin_unlock(&lun->lun_sep_lock); \
+ \
+ if (old) \
+ kfree_rcu(old, rcu_head); \
+ \
+ return size; \
+ \
+err: \
+ if (new) \
+ kfree(new); \
+ return ret; \
+}
+
+static void scsi_port_stats_hist_observe_bsearch(
+ struct scsi_port_stats_hist *hist, u64 val)
+{
+ size_t start = 0, end = hist->count - 1;
+
+ while (start < end) {
+ size_t mid = start + (end - start) / 2;
+
+ if (val < hist->items[mid])
+ end = mid;
+ else
+ start = mid + 1;
+ }
+
+ atomic64_inc(&hist->counters[start]);
+}
+
+void scsi_port_stats_hist_observe(
+ struct scsi_port_stats_hist *hist, u64 val)
+{
+ if (!hist)
+ return;
+
+ scsi_port_stats_hist_observe_bsearch(hist, val);
+}
+
+static ssize_t find_token(const char *page, size_t size,
+ size_t offset, size_t *token_len)
+{
+ size_t i;
+ ssize_t pos = -1;
+ size_t len = 0;
+
+ BUG_ON(offset > size);
+
+ for (i = offset; i < size; ++i) {
+ if (isspace(page[i])) {
+ if (len)
+ break;
+ } else if (!len++) {
+ pos = i;
+ }
+ }
+
+ if (pos > -1)
+ *token_len = len;
+
+ return pos;
+}
+
+static ssize_t read_histogram_items(const char *page, size_t size,
+ u64 *items, u8 items_max)
+{
+ u8 total = 0;
+ size_t token_len = 0;
+ ssize_t pos;
+
+ if (size == 0)
+ return 0;
+
+ pos = find_token(page, size, 0, &token_len);
+ if (pos == -1)
+ return 0;
+
+ while (pos != -1) {
+ int ret;
+ char buf[64];
+ u64 item;
+
+ if (token_len >= sizeof(buf))
+ return -EINVAL;
+
+ if (total + 1 == items_max) {
+ pr_err("items count can't be greater than %d: %d",
+ items_max, -EPERM);
+ return -EPERM;
+ }
+
+ memcpy(buf, page + pos, token_len);
+ buf[token_len] = 0;
+
+ ret = kstrtou64(buf, 10, &item);
+ if (ret < 0) {
+ pr_err("kstrtou64() failed for an item '%s': %d",
+ buf, ret);
+ return ret;
+ }
+
+ if ((item <= 0) || (total && item <= items[total - 1])) {
+ pr_err("items must be positive, unique and sorted: %d",
+ -EINVAL);
+ return -EINVAL;
+ }
+
+ items[total++] = item;
+ pos = find_token(page, size, pos + token_len, &token_len);
+ }
+
+ return total;
+}
+
+static ssize_t snprintf_histogram(char *page, size_t size,
+ struct scsi_port_stats_hist *hist)
+{
+ ssize_t ret = 0;
+ u8 i;
+
+ if (!hist)
+ return 0;
+
+ for (i = 0; i < hist->count - 1; ++i)
+ ret += snprintf(page + ret, PAGE_SIZE - ret,
+ "%llu ", (u64)atomic64_read(&hist->counters[i]));
+
+ ret += snprintf(page + ret, PAGE_SIZE - ret,
+ "%llu\n", (u64)atomic64_read(&hist->counters[i]));
+
+ return ret;
+}
+
+DEV_STAT_SCSI_TGT_PORT_STORE_HIST(read_hist);
+DEV_STAT_SCSI_TGT_PORT_SHOW_HIST(read_hist);
+DEV_STAT_SCSI_TGT_PORT_ATTR(read_hist, 0644);
+
+DEV_STAT_SCSI_TGT_PORT_STORE_HIST(write_hist);
+DEV_STAT_SCSI_TGT_PORT_SHOW_HIST(write_hist);
+DEV_STAT_SCSI_TGT_PORT_ATTR(write_hist, 0644);
+
+DEV_STAT_SCSI_TGT_PORT_STORE_HIST(sync_hist);
+DEV_STAT_SCSI_TGT_PORT_SHOW_HIST(sync_hist);
+DEV_STAT_SCSI_TGT_PORT_ATTR(sync_hist, 0644);
+
DEV_STAT_SCSI_TGT_PORT_STATS_SHOW_SIMPLE(read_bytes, tx_data_octets);
DEV_STAT_SCSI_TGT_PORT_ATTR_RO(read_bytes);
@@ -926,6 +1130,9 @@ static struct configfs_attribute *target_stat_scsi_tgt_port_attrs[] = {
&target_stat_scsi_tgt_port_bidi_errors.attr,
&target_stat_scsi_tgt_port_aborts.attr,
&target_stat_scsi_tgt_port_queue_cmds.attr,
+ &target_stat_scsi_tgt_port_read_hist.attr,
+ &target_stat_scsi_tgt_port_write_hist.attr,
+ &target_stat_scsi_tgt_port_sync_hist.attr,
NULL,
};
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 17442d5b686..eb1e9a323cf 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -854,6 +854,8 @@ void core_tpg_remove_lun(
struct se_portal_group *tpg,
struct se_lun *lun)
{
+ struct scsi_port_stats_hist *write_hist, *read_hist, *sync_hist;
+
core_clear_lun_from_tpg(lun, tpg);
transport_clear_lun_ref(lun);
@@ -863,5 +865,30 @@ void core_tpg_remove_lun(
lun->lun_status = TRANSPORT_LUN_STATUS_FREE;
spin_unlock(&tpg->tpg_lun_lock);
+ spin_lock(&lun->lun_sep_lock);
+
+ write_hist = rcu_dereference_protected(lun->lun_stats.write_hist,
+ lockdep_is_held(&lun->lun_sep_lock));
+ rcu_assign_pointer(lun->lun_stats.write_hist, NULL);
+
+ read_hist = rcu_dereference_protected(lun->lun_stats.read_hist,
+ lockdep_is_held(&lun->lun_sep_lock));
+ rcu_assign_pointer(lun->lun_stats.read_hist, NULL);
+
+ sync_hist = rcu_dereference_protected(lun->lun_stats.sync_hist,
+ lockdep_is_held(&lun->lun_sep_lock));
+ rcu_assign_pointer(lun->lun_stats.sync_hist, NULL);
+
+ spin_unlock(&lun->lun_sep_lock);
+
+ if (write_hist)
+ kfree_rcu(write_hist, rcu_head);
+
+ if (read_hist)
+ kfree_rcu(read_hist, rcu_head);
+
+ if (sync_hist)
+ kfree_rcu(sync_hist, rcu_head);
+
percpu_ref_exit(&lun->lun_ref);
}
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index f9d1491b08f..b27c17bda01 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -712,6 +712,7 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
} else if (!success) {
INIT_WORK(&cmd->work, target_complete_failure_work);
} else {
+ cmd->finished_exec_at = ktime_get_ns() / NSEC_PER_USEC;
INIT_WORK(&cmd->work, target_complete_ok_work);
}
@@ -1709,6 +1710,7 @@ void __target_execute_cmd(struct se_cmd *cmd)
sense_reason_t ret;
if (cmd->execute_cmd) {
+ cmd->started_exec_at = ktime_get_ns() / NSEC_PER_USEC;
ret = cmd->execute_cmd(cmd);
if (ret) {
spin_lock_irq(&cmd->t_state_lock);
@@ -2039,6 +2041,15 @@ static void target_complete_ok_work(struct work_struct *work)
}
queue_rsp:
+ if (cmd->t_task_cdb[0] == SYNCHRONIZE_CACHE ||
+ cmd->t_task_cdb[0] == SYNCHRONIZE_CACHE_16) {
+ rcu_read_lock();
+ scsi_port_stats_hist_observe(
+ rcu_dereference(cmd->se_lun->lun_stats.sync_hist),
+ cmd->finished_exec_at - cmd->started_exec_at);
+ rcu_read_unlock();
+ }
+
switch (cmd->data_direction) {
case DMA_FROM_DEVICE:
atomic_long_add(cmd->data_length,
@@ -2046,6 +2057,12 @@ queue_rsp:
atomic_long_inc(&cmd->se_lun->lun_stats.read_cmds);
+ rcu_read_lock();
+ scsi_port_stats_hist_observe(
+ rcu_dereference(cmd->se_lun->lun_stats.read_hist),
+ cmd->finished_exec_at - cmd->started_exec_at);
+ rcu_read_unlock();
+
/*
* Perform READ_STRIP of PI using software emulation when
* backend had PI enabled, if the transport will not be
@@ -2076,6 +2093,12 @@ queue_rsp:
atomic_long_inc(&cmd->se_lun->lun_stats.bidi_cmds) :
atomic_long_inc(&cmd->se_lun->lun_stats.write_cmds);
+ rcu_read_lock();
+ scsi_port_stats_hist_observe(
+ rcu_dereference(cmd->se_lun->lun_stats.write_hist),
+ cmd->finished_exec_at - cmd->started_exec_at);
+ rcu_read_unlock();
+
/*
* Check if we need to send READ payload for BIDI-COMMAND
*/
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 83538ca9f7c..8cfc2c11287 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -573,6 +573,8 @@ struct se_cmd {
sense_reason_t pi_err;
sector_t bad_sector;
bool prot_pto;
+ u64 started_exec_at;
+ u64 finished_exec_at;
};
struct se_ua {
@@ -710,6 +712,17 @@ struct se_port_stat_grps {
struct config_group scsi_transport_group;
};
+#define TCM_SE_PORT_STATS_HIST_MAX 40
+
+struct scsi_port_stats_hist {
+ u64 items[TCM_SE_PORT_STATS_HIST_MAX];
+ atomic64_t counters[TCM_SE_PORT_STATS_HIST_MAX];
+ u8 count;
+ struct rcu_head rcu_head;
+};
+
+void scsi_port_stats_hist_observe(struct scsi_port_stats_hist *hist, u64 val);
+
struct scsi_port_stats {
atomic_long_t cmd_pdus;
atomic_long_t tx_data_octets;
@@ -722,6 +735,9 @@ struct scsi_port_stats {
atomic_long_t bidi_errors;
atomic_long_t queue_cmds;
atomic_long_t aborts;
+ struct scsi_port_stats_hist __rcu *read_hist;
+ struct scsi_port_stats_hist __rcu *write_hist;
+ struct scsi_port_stats_hist __rcu *sync_hist;
};
struct se_lun {
--
2.11.0
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