• Jens Axboe's avatar
    block: add scalable completion tracking of requests · cf43e6be
    Jens Axboe authored
    For legacy block, we simply track them in the request queue. For
    blk-mq, we track them on a per-sw queue basis, which we can then
    sum up through the hardware queues and finally to a per device
    The stats are tracked in, roughly, 0.1s interval windows.
    Add sysfs files to display the stats.
    The feature is off by default, to avoid any extra overhead. In-kernel
    users of it can turn it on by setting QUEUE_FLAG_STATS in the queue
    flags. We currently don't turn it on if someone just reads any of
    the stats files, that is something we could add as well.
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
blk-sysfs.c 20 KB