From: Pavel Begunkov <[email protected]>
To: Miklos Szeredi <[email protected]>
Cc: Pavel Machek <[email protected]>,
Greg KH <[email protected]>,
Jan Ziak <[email protected]>,
Linux API <[email protected]>,
[email protected], [email protected],
[email protected],
linux-man <[email protected]>,
Michael Kerrisk <[email protected]>,
[email protected], Al Viro <[email protected]>,
[email protected]
Subject: Re: [PATCH 0/3] readfile(2): a new syscall to make open/read/close faster
Date: Wed, 15 Jul 2020 11:49:36 +0300 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAJfpegvkw5Exptz=gY5bRy2U8GjvTo+muBHsgdF_PA5=hyhmSA@mail.gmail.com>
On 15/07/2020 11:41, Miklos Szeredi wrote:
> On Wed, Jul 15, 2020 at 10:33 AM Pavel Begunkov <[email protected]> wrote:
>>
>> On 14/07/2020 14:55, Miklos Szeredi wrote:
>>> On Tue, Jul 14, 2020 at 1:36 PM Pavel Begunkov <[email protected]> wrote:
>>>>
>>>> On 14/07/2020 11:07, Miklos Szeredi wrote:
>>>>> On Tue, Jul 14, 2020 at 8:51 AM Pavel Machek <[email protected]> wrote:
>>>>>>
>>>>>> Hi!
>>>>>>
>>>>>>>> At first, I thought that the proposed system call is capable of
>>>>>>>> reading *multiple* small files using a single system call - which
>>>>>>>> would help increase HDD/SSD queue utilization and increase IOPS (I/O
>>>>>>>> operations per second) - but that isn't the case and the proposed
>>>>>>>> system call can read just a single file.
>>>>>>>
>>>>>>> If you want to do this for multple files, use io_ring, that's what it
>>>>>>> was designed for. I think Jens was going to be adding support for the
>>>>>>> open/read/close pattern to it as well, after some other more pressing
>>>>>>> features/fixes were finished.
>>>>>>
>>>>>> What about... just using io_uring for single file, too? I'm pretty
>>>>>> sure it can be wrapped in a library that is simple to use, avoiding
>>>>>> need for new syscall.
>>>>>
>>>>> Just wondering: is there a plan to add strace support to io_uring?
>>>>> And I don't just mean the syscalls associated with io_uring, but
>>>>> tracing the ring itself.
>>>>
>>>> What kind of support do you mean? io_uring is asynchronous in nature
>>>> with all intrinsic tracing/debugging/etc. problems of such APIs.
>>>> And there are a lot of handy trace points, are those not enough?
>>>>
>>>> Though, this can be an interesting project to rethink how async
>>>> APIs are worked with.
>>>
>>> Yeah, it's an interesting problem. The uring has the same events, as
>>> far as I understand, that are recorded in a multithreaded strace
>>> output (syscall entry, syscall exit); nothing more is needed>
>>> I do think this needs to be integrated into strace(1), otherwise the
>>> usefulness of that tool (which I think is *very* high) would go down
>>> drastically as io_uring usage goes up.
>>
>> Not touching the topic of usefulness of strace + io_uring, but I'd rather
>> have a tool that solves a problem, than a problem that created and honed
>> for a tool.
>
> Sorry, I'm not getting the metaphor. Can you please elaborate?
Sure, I mean _if_ there are tools that conceptually suit better, I'd
prefer to work with them, then trying to shove a new and possibly alien
infrastructure into strace.
But my knowledge of strace is very limited, so can't tell whether that's
the case. E.g. can it utilise static trace points?
--
Pavel Begunkov
next prev parent reply other threads:[~2020-07-15 8:51 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAODFU0q6CrUB_LkSdrbp5TQ4Jm6Sw=ZepZwD-B7-aFudsOvsig@mail.gmail.com>
[not found] ` <[email protected]>
[not found] ` <20200714065110.GA8047@amd>
2020-07-14 8:07 ` [PATCH 0/3] readfile(2): a new syscall to make open/read/close faster Miklos Szeredi
2020-07-14 11:34 ` Pavel Begunkov
2020-07-14 11:55 ` Miklos Szeredi
2020-07-15 8:31 ` Pavel Begunkov
2020-07-15 8:41 ` Miklos Szeredi
2020-07-15 8:49 ` Pavel Begunkov [this message]
2020-07-15 9:00 ` Pavel Begunkov
2020-07-15 11:17 ` Miklos Szeredi
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