Hi Fam,
On Thu, Nov 06, 2014 at 08:44:36PM +0800, Fam Zheng wrote:
> In this case, it is basically a polling. Let's not involve timer at all
> because that would hurt performance for application event loops.
>
> In an arbitrary test I've done, io_getevents syscall elapsed time
> reduces from 50000+ nanoseconds to a few hundereds.
This looks quite reasonable. I've applied this to my aio-next tree.
-ben
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> fs/aio.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 84a7510..7c0b561 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1221,8 +1221,12 @@ static long read_events(struct kioctx *ctx, long
> min_nr, long nr,
> * the ringbuffer empty. So in practice we should be ok, but it's
> * something to be aware of when touching this code.
> */
> - wait_event_interruptible_hrtimeout(ctx->wait,
> - aio_read_events(ctx, min_nr, nr, event, &ret), until);
> + if (until.tv64 == 0)
> + aio_read_events(ctx, min_nr, nr, event, &ret);
> + else
> + wait_event_interruptible_hrtimeout(ctx->wait,
> + aio_read_events(ctx, min_nr, nr, event, &ret),
> + until);
>
> if (!ret && signal_pending(current))
> ret = -EINTR;
> --
> 1.9.3
--
"Thought is the essence of where you are now."
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