From: Jes Sorensen <jsorensen@xxxxxx> Hi, This patchset introduces statistics collection of request sizes and latencies for blk-mq using the blk-stat infrastructue. This was designed to have minimal overhead when not in use. It relies on blk_rq_stats_sectors() and introduces a sectors counter to struct blk_rq_stat. For request sizes it uses 8 buckets per operation type. Latencies are tracked in us precision, and uses 32 buckets per operation type. To not blow up the size of struct request_queue, I changed it to dynamically allocate these data structures. Usage, request stats are enabled like this: $ echo 1 > /sys/block/nvme0n1/queue/reqstat with output reading like this: $ cat /sys/block/nvme0n1/queue/stat read: 0 0 0 8278016 14270464 29323264 120107008 2069282816 read reqs: 0 0 0 2021 1531 1377 3229 3627 write: 4096 0 3072 10903552 9244672 6258688 16584704 2228011008 write reqs: 8 0 1 2662 898 311 375 4972 discard: 0 0 0 5242880 5472256 3809280 136880128 830554112 discard reqs: 0 0 0 1280 515 196 4150 3717 Latency stats are enabled like this: $ echo 1 > /sys/block/nvme0n1/queue/latstat with output reading like this $ cat /sys/block/nvme0n1/queue/latency read: 0 0 0 0 4 101 677 5146 1162 2654 1933 832 657 52 8 0 3 2 3 2 0 0 0 0 0 0 0 0 0 0 0 0 write: 0 0 0 79 2564 2641 8087 6226 1580 4052 498 332 385 365 382 279 323 166 109 119 188 267 0 0 0 0 0 0 0 0 0 0 discard: 0 0 0 0 0 0 0 17709 698 15 0 1 0 0 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Cheers, Jes Jes Sorensen (7): block: keep track of per-device io sizes in stats block: Use blk-stat infrastructure to collect per queue request stats Export block request stats to sysfs Expand block stats to export number of of requests per bucket blk-mq: Only allocate request stat data when it is enabled blk-stat: Make bucket function take latency as an additional argument block: Introduce blk-mq latency stats block/blk-iolatency.c | 2 +- block/blk-mq.c | 110 ++++++++++++++++++++- block/blk-stat.c | 18 ++-- block/blk-stat.h | 12 ++- block/blk-sysfs.c | 195 ++++++++++++++++++++++++++++++++++++++ block/blk-wbt.c | 2 +- include/linux/blk_types.h | 1 + include/linux/blkdev.h | 13 +++ 8 files changed, 338 insertions(+), 15 deletions(-) -- 2.17.1
