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authorTejun Heo <tj@kernel.org>2019-09-25 16:02:07 -0700
committerJens Axboe <axboe@kernel.dk>2019-09-26 01:11:58 -0600
commit25d41e4aadb0788b4fae8a8fca90f437b9ebd727 (patch)
treec6bf9df51f0bb42339a3c2c929b990b2c485fc48 /block/blk-iocost.c
parentb89f625e28d44552083f43752f62d8621ded0a04 (diff)
downloadlinux-25d41e4aadb0788b4fae8a8fca90f437b9ebd727.tar.bz2
iocost: better trace vrate changes
vrate_adj tracepoint traces vrate changes; however, it does so only when busy_level is non-zero. busy_level turning to zero can sometimes be as interesting an event. This patch also enables vrate_adj tracepoint on other vrate related events - busy_level changes and non-zero nr_lagging. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-iocost.c')
-rw-r--r--block/blk-iocost.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 3b39deb8b9f8..32d4d6d86a99 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1343,7 +1343,7 @@ static void ioc_timer_fn(struct timer_list *timer)
u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];
u32 missed_ppm[2], rq_wait_pct;
u64 period_vtime;
- int i;
+ int prev_busy_level, i;
/* how were the latencies during the period? */
ioc_lat_stat(ioc, missed_ppm, &rq_wait_pct);
@@ -1531,6 +1531,7 @@ skip_surplus_transfers:
* and experiencing shortages but not surpluses, we're too stingy
* and should increase vtime rate.
*/
+ prev_busy_level = ioc->busy_level;
if (rq_wait_pct > RQ_WAIT_BUSY_PCT ||
missed_ppm[READ] > ppm_rthr ||
missed_ppm[WRITE] > ppm_wthr) {
@@ -1592,6 +1593,10 @@ skip_surplus_transfers:
atomic64_set(&ioc->vtime_rate, vrate);
ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP(
ioc->period_us * vrate * INUSE_MARGIN_PCT, 100);
+ } else if (ioc->busy_level != prev_busy_level || nr_lagging) {
+ trace_iocost_ioc_vrate_adj(ioc, atomic64_read(&ioc->vtime_rate),
+ &missed_ppm, rq_wait_pct, nr_lagging,
+ nr_shortages, nr_surpluses);
}
ioc_refresh_params(ioc, false);