From: Jens Axboe <axboe@kernel.dk>
To: Jeff Moyer <jmoyer@redhat.com>
Cc: linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-aio@kvack.org, hch@lst.de
Subject: Re: [PATCH 08/26] aio: don't zero entire aio_kiocb aio_get_req()
Date: Thu, 6 Dec 2018 12:42:58 -0700 [thread overview]
Message-ID: <72e91bed-b135-2d6a-c26a-bf65afed990c@kernel.dk> (raw)
In-Reply-To: <x49pnuefnt0.fsf@segfault.boston.devel.redhat.com>
On 12/6/18 12:38 PM, Jeff Moyer wrote:
> Jens Axboe <axboe@kernel.dk> writes:
>
>> On 12/6/18 12:27 PM, Jeff Moyer wrote:
>>> Jens Axboe <axboe@kernel.dk> writes:
>>>
>>>> It's 192 bytes, fairly substantial. Most items don't need to be cleared,
>>>> especially not upfront. Clear the ones we do need to clear, and leave
>>>> the other ones for setup when the iocb is prepared and submitted.
>>>
>>> What performance gains do you see from this?
>>
>> Before this, I had 1% in memset doing high IOPS. With it, that's gone.
>> 1% is a lot, when you have just one thread doing everything from submission
>> to completion.
>
> I'm used to customers complaining about fractions of a percent, so I get
> it. :-) I just wanted to know we had some measurable impact, as I've
> seen bugs crop up from code like this in the past.
Oh for sure, I wouldn't do it if there wasn't a noticeable gain from this!
--
Jens Axboe
next prev parent reply other threads:[~2018-12-06 19:43 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 23:37 [PATCHSET v5] Support for polled aio Jens Axboe
2018-12-04 23:37 ` [PATCH 01/26] fs: add an iopoll method to struct file_operations Jens Axboe
2018-12-06 19:16 ` Jeff Moyer
2018-12-04 23:37 ` [PATCH 02/26] block: add REQ_HIPRI_ASYNC Jens Axboe
2018-12-04 23:37 ` [PATCH 03/26] block: wire up block device iopoll method Jens Axboe
2018-12-06 19:11 ` Jeff Moyer
2018-12-06 19:14 ` Jens Axboe
2018-12-06 19:15 ` Christoph Hellwig
2018-12-06 19:25 ` Jens Axboe
2018-12-04 23:37 ` [PATCH 04/26] block: use REQ_HIPRI_ASYNC for non-sync polled IO Jens Axboe
2018-12-04 23:37 ` [PATCH 05/26] iomap: wire up the iopoll method Jens Axboe
2018-12-04 23:37 ` [PATCH 06/26] aio: use assigned completion handler Jens Axboe
2018-12-04 23:37 ` [PATCH 07/26] aio: separate out ring reservation from req allocation Jens Axboe
2018-12-04 23:37 ` [PATCH 08/26] aio: don't zero entire aio_kiocb aio_get_req() Jens Axboe
2018-12-06 19:27 ` Jeff Moyer
2018-12-06 19:28 ` Jens Axboe
2018-12-06 19:38 ` Jeff Moyer
2018-12-06 19:42 ` Jens Axboe [this message]
2018-12-04 23:37 ` [PATCH 09/26] aio: only use blk plugs for > 2 depth submissions Jens Axboe
2018-12-06 19:29 ` Jeff Moyer
2018-12-06 19:31 ` Jens Axboe
2018-12-04 23:37 ` [PATCH 10/26] aio: use iocb_put() instead of open coding it Jens Axboe
2018-12-04 23:37 ` [PATCH 11/26] aio: split out iocb copy from io_submit_one() Jens Axboe
2018-12-04 23:37 ` [PATCH 12/26] aio: abstract out io_event filler helper Jens Axboe
2018-12-04 23:37 ` [PATCH 13/26] aio: add io_setup2() system call Jens Axboe
2018-12-04 23:37 ` [PATCH 14/26] aio: add support for having user mapped iocbs Jens Axboe
2018-12-04 23:37 ` [PATCH 15/26] aio: support for IO polling Jens Axboe
2018-12-05 9:56 ` Benny Halevy
2018-12-05 13:10 ` Jens Axboe
2018-12-06 9:04 ` Benny Halevy
2018-12-04 23:37 ` [PATCH 16/26] aio: add submission side request cache Jens Axboe
2018-12-04 23:37 ` [PATCH 17/26] fs: add fget_many() and fput_many() Jens Axboe
2018-12-04 23:37 ` [PATCH 18/26] aio: use fget/fput_many() for file references Jens Axboe
2018-12-04 23:37 ` [PATCH 19/26] aio: split iocb init from allocation Jens Axboe
2018-12-04 23:37 ` [PATCH 20/26] aio: batch aio_kiocb allocation Jens Axboe
2018-12-04 23:37 ` [PATCH 21/26] block: add BIO_HOLD_PAGES flag Jens Axboe
2018-12-04 23:37 ` [PATCH 22/26] block: implement bio helper to add iter bvec pages to bio Jens Axboe
2018-12-04 23:37 ` [PATCH 23/26] fs: add support for mapping an ITER_BVEC for O_DIRECT Jens Axboe
2018-12-04 23:37 ` [PATCH 24/26] aio: add support for pre-mapped user IO buffers Jens Axboe
2018-12-04 23:37 ` [PATCH 25/26] aio: split old ring complete out from aio_complete() Jens Axboe
2018-12-04 23:37 ` [PATCH 26/26] aio: add support for submission/completion rings Jens Axboe
2018-12-07 18:48 ` [PATCHSET v5] Support for polled aio Jeff Moyer
2018-12-07 18:52 ` Jens Axboe
2018-12-07 18:55 ` Jens Axboe
2018-12-07 19:34 ` Jeff Moyer
2018-12-07 19:35 ` Jens Axboe
2018-12-07 21:58 ` Jens Axboe
2018-12-07 21:59 ` Jens Axboe
2018-12-07 22:00 ` Jens Axboe
2018-12-07 22:06 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2018-12-07 22:19 [PATCHSET v6] Support for polled aio (and more) Jens Axboe
2018-12-07 22:19 ` [PATCH 08/26] aio: don't zero entire aio_kiocb aio_get_req() Jens Axboe
2018-12-13 17:56 [PATCHSET v8] Support for polled and buffered aio (and more) Jens Axboe
2018-12-13 17:56 ` [PATCH 08/26] aio: don't zero entire aio_kiocb aio_get_req() Jens Axboe
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