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From: Paolo Valente <paolo.valente@linaro.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	ulf.hansson@linaro.org, linus.walleij@linaro.org,
	bfq-iosched@googlegroups.com, oleksandr@natalenko.name,
	Paolo Valente <paolo.valente@linaro.org>
Subject: [PATCH 3/4] block, bfq: increase update frequency of inject limit
Date: Thu, 22 Aug 2019 17:20:36 +0200	[thread overview]
Message-ID: <20190822152037.15413-4-paolo.valente@linaro.org> (raw)
In-Reply-To: <20190822152037.15413-1-paolo.valente@linaro.org>

The update period of the injection limit has been tentatively set to
100 ms, to reduce fluctuations. This value however proved to cause,
occasionally, the limit to be decremented for some bfq_queue only
after the queue underwent excessive injection for a lot of time. This
commit reduces the period to 10 ms.

Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
---
 block/bfq-iosched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index e114282204f6..ddac93e910fa 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2016,7 +2016,7 @@ static void bfq_add_request(struct request *rq)
 		     (bfqq->last_serv_time_ns > 0 &&
 		      bfqd->rqs_injected && bfqd->rq_in_driver > 0)) &&
 		    time_is_before_eq_jiffies(bfqq->decrease_time_jif +
-					      msecs_to_jiffies(100))) {
+					      msecs_to_jiffies(10))) {
 			bfqd->last_empty_occupied_ns = ktime_get_ns();
 			/*
 			 * Start the state machine for measuring the
-- 
2.20.1


  parent reply	other threads:[~2019-08-22 15:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-22 15:20 [PATCH 0/4] block, bfq: series of improvements and small fixes of the injection mechanism Paolo Valente
2019-08-22 15:20 ` [PATCH 1/4] block, bfq: update inject limit only after injection occurred Paolo Valente
2019-08-22 15:20 ` [PATCH 2/4] block, bfq: reduce upper bound for inject limit to max_rq_in_driver+1 Paolo Valente
2019-08-22 15:20 ` Paolo Valente [this message]
2019-08-22 15:20 ` [PATCH 4/4] block, bfq: push up injection only after setting service time Paolo Valente
2019-09-09  5:57 ` [PATCH 0/4] block, bfq: series of improvements and small fixes of the injection mechanism Paolo Valente
2019-09-09  6:03 ` Oleksandr Natalenko
2019-09-16 15:32   ` Paolo Valente
2019-09-16 16:17 ` Jens Axboe

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