From: Jens Axboe <axboe@kernel.dk>
To: Pavel Begunkov <asml.silence@gmail.com>,
Andres Freund <andres@anarazel.de>,
io-uring@vger.kernel.org
Subject: Re: liburing: expose syscalls?
Date: Sat, 1 Feb 2020 20:29:39 -0700 [thread overview]
Message-ID: <502b2b01-d691-b7bf-53f1-e7a24fb4c6d9@kernel.dk> (raw)
In-Reply-To: <9644308d-ef0e-1b94-9a3b-1a4e03bfd314@gmail.com>
On 2/1/20 4:30 PM, Pavel Begunkov wrote:
> On 02/02/2020 01:51, Jens Axboe wrote:
>>>> So you just want to have them exposed? I'd be fine with that. I'll
>>>> take a patch :-)
>>>>
>>>
>>> Depends on how it's used, but I'd strive to inline
>>> __sys_io_uring_enter() to remove the extra indirect call into the
>>> shared lib. Though, not sure about packaging and all this stuff. May
>>> be useful to do that for liburing as well.
>>
>> Not sure that actually matters when you're doing a syscall anyway, that
>> should be the long pole for the operation.
>>
>
> Yeah, but they are starting to stack up (+syscall() from glibc) and can became
> even more layered on the user side.
Not saying it's free, just that I expect the actual system call to dominate.
But I hear what you are saying, this is exactly why the liburing hot path
resides in static inline code, and doesn't require library calls. I did
draw the line on anything that needs a system call, figuring that wasn't
worth over-optimizing.
I could be full of shit, numbers talk!
--
Jens Axboe
next prev parent reply other threads:[~2020-02-02 3:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-01 12:53 liburing: expose syscalls? Andres Freund
2020-02-01 17:39 ` Jens Axboe
2020-02-01 17:49 ` Andres Freund
2020-02-01 17:52 ` Jens Axboe
2020-02-01 21:16 ` Pavel Begunkov
2020-02-01 22:51 ` Jens Axboe
2020-02-01 23:30 ` Pavel Begunkov
2020-02-02 3:29 ` Jens Axboe [this message]
2020-02-02 7:27 ` Andres Freund
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