From eb2fd80f9d2c515a901599362e83bc3356fc5e97 Mon Sep 17 00:00:00 2001 From: Paolo Valente Date: Mon, 25 Jan 2021 20:02:43 +0100 Subject: block, bfq: replace mechanism for evaluating I/O intensity Some BFQ mechanisms make their decisions on a bfq_queue basing also on whether the bfq_queue is I/O bound. In this respect, the current logic for evaluating whether a bfq_queue is I/O bound is rather rough. This commits replaces this logic with a more effective one. The new logic measures the percentage of time during which a bfq_queue is active, and marks the bfq_queue as I/O bound if the latter if this percentage is above a fixed threshold. Tested-by: Jan Kara Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-iosched.h | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'block/bfq-iosched.h') diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index 703895224562..c913b06016b3 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -291,6 +291,11 @@ struct bfq_queue { /* associated @bfq_ttime struct */ struct bfq_ttime ttime; + /* when bfqq started to do I/O within the last observation window */ + u64 io_start_time; + /* how long bfqq has remained empty during the last observ. window */ + u64 tot_idle_time; + /* bit vector: a 1 for each seeky requests in history */ u32 seek_history; @@ -407,6 +412,9 @@ struct bfq_io_cq { */ bool saved_IO_bound; + u64 saved_io_start_time; + u64 saved_tot_idle_time; + /* * Same purpose as the previous fields for the value of the * field keeping the queue's belonging to a large burst @@ -641,14 +649,6 @@ struct bfq_data { */ unsigned int bfq_timeout; - /* - * Number of consecutive requests that must be issued within - * the idle time slice to set again idling to a queue which - * was marked as non-I/O-bound (see the definition of the - * IO_bound flag for further details). - */ - unsigned int bfq_requests_within_timer; - /* * Force device idling whenever needed to provide accurate * service guarantees, without caring about throughput -- cgit v1.2.3