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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 11:31:23 +0300	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAJfpegvroouw5ndHv+395w5PP1c+pUyp=-T8qhhvSnFbhbRehg@mail.gmail.com>

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.

-- 
Pavel Begunkov

  reply	other threads:[~2020-07-15  8:33 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 [this message]
2020-07-15  8:41             ` Miklos Szeredi
2020-07-15  8:49               ` Pavel Begunkov
2020-07-15  9:00                 ` Pavel Begunkov
2020-07-15 11:17                   ` Miklos Szeredi

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