lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 6 Nov 2006 01:42:32 -0500 (EST)
From:	Brent Baccala <cosine@...esoft.org>
To:	Jens Axboe <jens.axboe@...cle.com>
cc:	linux-kernel@...r.kernel.org
Subject: Re: async I/O seems to be blocking on 2.6.15

On Sun, 5 Nov 2006, Jens Axboe wrote:

> On Fri, Nov 03 2006, Brent Baccala wrote:
>>
>> Does 7 microseconds seem a bit excessive for an io_submit (and a
>> gettimeofday)?
>
> I guess you mean miliseconds, not microseconds. 7 miliseconds seems way
> too long. I repeated your test here, and the 100 submits take 97000
> microseconds here - or 97 miliseconds. So that's a little less than 1
> msec per io_submit. Still pretty big. You can experiment with oprofile
> to profile where the kernel spends its time in that period.
>
> -- 
> Jens Axboe
>

Yes, of course, milliseconds.  I have enough other problems with this
program (measured in minutes, and no mistake that) that I doubt I'll
be profiling the kernel any time soon, but thank you for your help.

More than anything else, you've made me understand that I can't just
fire off a bunch of async requests like I'm tossing peanuts across the
table.  I've really got to pay attention to what's in that kernel
queue and how it gets managed.



 					-bwb

 					Brent Baccala
 					cosine@...esoft.org
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists