Re: [PATCH 1/2] Add poll_considered statistic

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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
> 

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux FS]     [Yosemite Forum]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux