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From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/2] optimise iov_iter
Date: Thu, 19 Nov 2020 18:02:44 +0000	[thread overview]
Message-ID: <bbaaf6fe-d456-a3b1-9f95-005e182eadfd@gmail.com> (raw)
In-Reply-To: <72a1df1a-810b-5bf1-39bd-b702188a875b@kernel.dk>

On 19/11/2020 17:20, Jens Axboe wrote:
> On 11/19/20 10:14 AM, Pavel Begunkov wrote:
>> On 19/11/2020 16:46, Jens Axboe wrote:
>>> On 11/19/20 8:29 AM, Pavel Begunkov wrote:
>>>> The first patch optimises iov_iter_npages() for the bvec case, and the
>>>> second helps code generation to kill unreachable code.
>>>>
>>>> Pavel Begunkov (2):
>>>>   iov_iter: optimise iov_iter_npages for bvec
>>>>   iov_iter: optimise iter type checking
>>>>
>>>>  include/linux/uio.h | 10 +++++-----
>>>>  lib/iov_iter.c      | 10 +++++-----
>>>>  2 files changed, 10 insertions(+), 10 deletions(-)
>>>
>>> Nice! Tested this and confirmed both the better code generation,
>>> and reduction in overhead in iov_iter_npages().
>>
>> Thanks! Did you find t-put/etc. boost with your setup?
> 
> Yeah, for this kind of test, if we shave 1% off the stack overhead,
> that directly yields an increase in peak IOPS. My numbers were close
> to yours, dropped about 1% of system overhead.

That's great. I was guessing how much of it can be due
to not cached bvec and was just tossed to somewhere else.

-- 
Pavel Begunkov

      reply	other threads:[~2020-11-19 18:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-19 15:29 [PATCH 0/2] optimise iov_iter Pavel Begunkov
2020-11-19 15:29 ` [PATCH 1/2] iov_iter: optimise iov_iter_npages for bvec Pavel Begunkov
2020-11-19 15:29 ` [PATCH 2/2] iov_iter: optimise iter type checking Pavel Begunkov
2020-11-19 17:03   ` Christoph Hellwig
2020-11-19 17:12     ` Pavel Begunkov
2020-12-11  2:01       ` Al Viro
2020-12-13 22:32         ` Pavel Begunkov
2020-12-14 10:28           ` David Laight
2020-12-14 17:25             ` Pavel Begunkov
2020-11-19 16:46 ` [PATCH 0/2] optimise iov_iter Jens Axboe
2020-11-19 17:14   ` Pavel Begunkov
2020-11-19 17:20     ` Jens Axboe
2020-11-19 18:02       ` Pavel Begunkov [this message]

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