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| author | Stephen Bates <sbates@raithlin.com> | 2016-09-13 12:23:15 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-09-14 08:41:21 -0600 |
| commit | 6e219353afa1f67f453141f7462b01708ebf5574 (patch) | |
| tree | d09924891e887e970be9a18442bebc40d2ad64ee /block | |
| parent | 0eadf37afc2500e1162c9040ec26a705b9af8d47 (diff) | |
| download | linux-stable-6e219353afa1f67f453141f7462b01708ebf5574.tar.gz linux-stable-6e219353afa1f67f453141f7462b01708ebf5574.tar.bz2 linux-stable-6e219353afa1f67f453141f7462b01708ebf5574.zip | |
block: add poll_considered statistic
In order to help determine the effectiveness of polling in a running
system it is usful to determine the ratio of how often the poll
function is called vs how often the completion is checked. For this
reason we add a poll_considered variable and add it to the sysfs entry
for io_poll.
Signed-off-by: Stephen Bates <sbates@raithlin.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 8 | ||||
| -rw-r--r-- | block/blk-mq-sysfs.c | 4 |
2 files changed, 9 insertions, 3 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index 34ff8088eebe..14d7c0740dc0 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -3307,19 +3307,23 @@ bool blk_poll(struct request_queue *q, blk_qc_t cookie) { struct blk_plug *plug; long state; + unsigned int queue_num; + struct blk_mq_hw_ctx *hctx; if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) || !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) return false; + queue_num = blk_qc_t_to_queue_num(cookie); + hctx = q->queue_hw_ctx[queue_num]; + hctx->poll_considered++; + plug = current->plug; if (plug) blk_flush_plug_list(plug, false); state = current->state; while (!need_resched()) { - unsigned int queue_num = blk_qc_t_to_queue_num(cookie); - struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num]; int ret; hctx->poll_invoked++; diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index fe822aa5b8e4..ea8c3f58afbd 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -176,7 +176,9 @@ static ssize_t blk_mq_sysfs_rq_list_show(struct blk_mq_ctx *ctx, char *page) static ssize_t blk_mq_hw_sysfs_poll_show(struct blk_mq_hw_ctx *hctx, char *page) { - return sprintf(page, "invoked=%lu, success=%lu\n", hctx->poll_invoked, hctx->poll_success); + return sprintf(page, "considered=%lu, invoked=%lu, success=%lu\n", + hctx->poll_considered, hctx->poll_invoked, + hctx->poll_success); } static ssize_t blk_mq_hw_sysfs_queued_show(struct blk_mq_hw_ctx *hctx, |