From: Brian Gianforcaro <[email protected]>
To: Pavel Begunkov <[email protected]>
Cc: Jens Axboe <[email protected]>,
[email protected], [email protected]
Subject: Re: [PATCH v4 2/2] io_uring: batch getting pcpu references
Date: Sun, 29 Dec 2019 19:33:22 -0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On Sat, Dec 28, 2019 at 09:37:35PM +0300, Pavel Begunkov wrote:
> On 28/12/2019 20:03, Jens Axboe wrote:
> > On 12/28/19 4:15 AM, Pavel Begunkov wrote:
> >> On 28/12/2019 14:13, Pavel Begunkov wrote:
> >>> percpu_ref_tryget() has its own overhead. Instead getting a reference
> >>> for each request, grab a bunch once per io_submit_sqes().
> >>>
> >>> ~5% throughput boost for a "submit and wait 128 nops" benchmark.
> >>>
> >>> Signed-off-by: Pavel Begunkov <[email protected]>
> >>> ---
> >>> fs/io_uring.c | 26 +++++++++++++++++---------
> >>> 1 file changed, 17 insertions(+), 9 deletions(-)
> >>>
> >>> diff --git a/fs/io_uring.c b/fs/io_uring.c
> >>> index 7fc1158bf9a4..404946080e86 100644
> >>> --- a/fs/io_uring.c
> >>> +++ b/fs/io_uring.c
> >>> @@ -1080,9 +1080,6 @@ static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
> >>> gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
> >>> struct io_kiocb *req;
> >>>
> >>> - if (!percpu_ref_tryget(&ctx->refs))
> >>> - return NULL;
> >>> -
> >>> if (!state) {
> >>> req = kmem_cache_alloc(req_cachep, gfp);
> >>> if (unlikely(!req))
> >>> @@ -1141,6 +1138,14 @@ static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
> >>> }
> >>> }
> >>>
> >>> +static void __io_req_free_empty(struct io_kiocb *req)
> >>
> >> If anybody have better naming (or a better approach at all), I'm all ears.
> >
> > __io_req_do_free()?
>
> Not quite clear what's the difference with __io_req_free() then
>
> >
> > I think that's better than the empty, not quite sure what that means.
>
> Probably, so. It was kind of "request without a bound sqe".
> Does io_free_{hollow,empty}_req() sound better?
Given your description, perhaps io_free_unbound_req() makes sense?
next prev parent reply other threads:[~2019-12-30 3:33 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 22:28 [PATCH 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-17 22:28 ` [PATCH 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-17 23:42 ` Jens Axboe
2019-12-18 16:26 ` Tejun Heo
2019-12-18 17:49 ` Dennis Zhou
2019-12-21 15:36 ` Pavel Begunkov
2019-12-17 22:28 ` [PATCH 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-17 23:21 ` Jens Axboe
2019-12-17 23:31 ` Jens Axboe
2019-12-18 9:25 ` Pavel Begunkov
2019-12-18 9:23 ` Pavel Begunkov
2019-12-18 0:02 ` Jens Axboe
2019-12-18 10:41 ` Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 0/3] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 1/3] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-21 16:15 ` [PATCH v2 2/3] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-21 16:15 ` [PATCH RFC v2 3/3] io_uring: batch get(ctx->ref) across submits Pavel Begunkov
2019-12-21 16:20 ` Pavel Begunkov
2019-12-21 16:38 ` Jens Axboe
2019-12-21 16:48 ` Pavel Begunkov
2019-12-21 17:01 ` Jens Axboe
2019-12-21 17:26 ` Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-21 20:12 ` [PATCH v3 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-21 21:56 ` Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 0/2] optimise ctx's refs grabbing in io_uring Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 1/2] pcpu_ref: add percpu_ref_tryget_many() Pavel Begunkov
2019-12-28 11:13 ` [PATCH v4 2/2] io_uring: batch getting pcpu references Pavel Begunkov
2019-12-28 11:15 ` Pavel Begunkov
2019-12-28 17:03 ` Jens Axboe
2019-12-28 18:37 ` Pavel Begunkov
2019-12-30 3:33 ` Brian Gianforcaro [this message]
2019-12-30 18:45 ` Pavel Begunkov
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