Commit 8cd5b8fc authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Jens Axboe
Browse files

block/diskstats: replace time_in_queue with sum of request times 



Column "time_in_queue" in diskstats is supposed to show total waiting time
of all requests. I.e. value should be equal to the sum of times from other
columns. But this is not true, because column "time_in_queue" is counted
separately in jiffies rather than in nanoseconds as other times.

This patch removes redundant counter for "time_in_queue" and shows total
time of read, write, discard and flush requests.

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent ea18e0f0

block/bio.c

+0 −1
Original line number Diff line number Diff line
@@ -1811,7 +1811,6 @@ void generic_end_io_acct(struct request_queue *q, int req_op, 


	update_io_ticks(part, now, true);

	part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));

	part_stat_add(part, time_in_queue, duration);

	part_dec_in_flight(q, part, op_is_write(req_op));



	part_stat_unlock();

block/blk-core.c

+0 −1
Original line number Diff line number Diff line
@@ -1340,7 +1340,6 @@ void blk_account_io_done(struct request *req, u64 now) 
		update_io_ticks(part, jiffies, true);

		part_stat_inc(part, ios[sgrp]);

		part_stat_add(part, nsecs[sgrp], now - req->start_time_ns);

		part_stat_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns));

		part_dec_in_flight(req->q, part, rq_data_dir(req));



		hd_struct_put(part);

block/genhd.c

+10 −3
Original line number Diff line number Diff line
@@ -110,7 +110,6 @@ static void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat) 
		}



		stat->io_ticks += ptr->io_ticks;

		stat->time_in_queue += ptr->time_in_queue;

	}

}

#else /* CONFIG_SMP */
@@ -1265,7 +1264,11 @@ ssize_t part_stat_show(struct device *dev, 
		(unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),

		inflight,

		jiffies_to_msecs(stat.io_ticks),

		jiffies_to_msecs(stat.time_in_queue),

		(unsigned int)div_u64(stat.nsecs[STAT_READ] +

				      stat.nsecs[STAT_WRITE] +

				      stat.nsecs[STAT_DISCARD] +

				      stat.nsecs[STAT_FLUSH],

						NSEC_PER_MSEC),

		stat.ios[STAT_DISCARD],

		stat.merges[STAT_DISCARD],

		(unsigned long long)stat.sectors[STAT_DISCARD],
@@ -1559,7 +1562,11 @@ static int diskstats_show(struct seq_file *seqf, void *v) 
							NSEC_PER_MSEC),

			   inflight,

			   jiffies_to_msecs(stat.io_ticks),

			   jiffies_to_msecs(stat.time_in_queue),

			   (unsigned int)div_u64(stat.nsecs[STAT_READ] +

						 stat.nsecs[STAT_WRITE] +

						 stat.nsecs[STAT_DISCARD] +

						 stat.nsecs[STAT_FLUSH],

							NSEC_PER_MSEC),

			   stat.ios[STAT_DISCARD],

			   stat.merges[STAT_DISCARD],

			   stat.sectors[STAT_DISCARD],

include/linux/genhd.h

+0 −1
Original line number Diff line number Diff line
@@ -46,7 +46,6 @@ struct disk_stats { 
	unsigned long ios[NR_STAT_GROUPS];

	unsigned long merges[NR_STAT_GROUPS];

	unsigned long io_ticks;

	unsigned long time_in_queue;

	local_t in_flight[2];

};

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