From 6f816b4b746c2241540e537682d30d8e9997d674 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 28 Aug 2019 15:05:57 -0700 Subject: blk-mq: add optional request->alloc_time_ns There are currently two start time timestamps - start_time_ns and io_start_time_ns. The former marks the request allocation and and the second issue-to-device time. The planned io.weight controller needs to measure the total time bios take to execute after it leaves rq_qos including the time spent waiting for request to become available, which can easily dominate on saturated devices. This patch adds request->alloc_time_ns which records when the request allocation attempt started. As it isn't used for the usual stats, make it optional behind CONFIG_BLK_RQ_ALLOC_TIME and QUEUE_FLAG_RQ_ALLOC_TIME so that it can be compiled out when there are no users and it's active only on queues which need it even when compiled in. v2: s/pre_start_time/alloc_time/ and add CONFIG_BLK_RQ_ALLOC_TIME gating as suggested by Jens. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/Kconfig | 3 +++ 1 file changed, 3 insertions(+) (limited to 'block/Kconfig') diff --git a/block/Kconfig b/block/Kconfig index 8b5f8e560eb4..1b62ad6d0e12 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -26,6 +26,9 @@ menuconfig BLOCK if BLOCK +config BLK_RQ_ALLOC_TIME + bool + config BLK_SCSI_REQUEST bool -- cgit v1.2.3