Commit 25d41e4a authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b89f625e

block/blk-iocost.c

+6 −1
Original line number Original line Diff line number Diff line
@@ -1343,7 +1343,7 @@ static void ioc_timer_fn(struct timer_list *timer) 
	u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];

	u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM];

	u32 missed_ppm[2], rq_wait_pct;

	u32 missed_ppm[2], rq_wait_pct;

	u64 period_vtime;

	u64 period_vtime;

	int i;

	int prev_busy_level, i;





	/* how were the latencies during the period? */

	/* how were the latencies during the period? */

	ioc_lat_stat(ioc, missed_ppm, &rq_wait_pct);

	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 experiencing shortages but not surpluses, we're too stingy

	 * and should increase vtime rate.

	 * and should increase vtime rate.

	 */

	 */

	prev_busy_level = ioc->busy_level;

	if (rq_wait_pct > RQ_WAIT_BUSY_PCT ||

	if (rq_wait_pct > RQ_WAIT_BUSY_PCT ||

	    missed_ppm[READ] > ppm_rthr ||

	    missed_ppm[READ] > ppm_rthr ||

	    missed_ppm[WRITE] > ppm_wthr) {

	    missed_ppm[WRITE] > ppm_wthr) {
@@ -1592,6 +1593,10 @@ skip_surplus_transfers: 
		atomic64_set(&ioc->vtime_rate, vrate);

		atomic64_set(&ioc->vtime_rate, vrate);

		ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP(

		ioc->inuse_margin_vtime = DIV64_U64_ROUND_UP(

			ioc->period_us * vrate * INUSE_MARGIN_PCT, 100);

			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);

	ioc_refresh_params(ioc, false);

CRA Git | Maintained and supported by SUSTech CRA and CCSE