Hi All
Apologies. That was the wrong patch. Please ignore.
Cheers
Stephen
> On Sep 25, 2016, at 6:41 PM, Stephen Bates <sbates@xxxxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxx>
> ---
> block/blk-core.c | 8 ++++++--
> block/blk-mq-sysfs.c | 4 +++-
> include/linux/blk-mq.h | 1 +
> 3 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 34ff808..14d7c07 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 fe822aa..ea8c3f5 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,
> diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
> index e1544f0..7710f79 100644
> --- a/include/linux/blk-mq.h
> +++ b/include/linux/blk-mq.h
> @@ -61,6 +61,7 @@ struct blk_mq_hw_ctx {
> struct blk_mq_cpu_notifier cpu_notifier;
> struct kobject kobj;
>
> + unsigned long poll_considered;
> unsigned long poll_invoked;
> unsigned long poll_success;
> };
> --
> 2.5.0
>
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