From: Goswin von Brederlow <goswin-v-b@web.de>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Re: How to read different ints from a Bigarray?
Date: Fri, 30 Oct 2009 00:38:55 +0100 [thread overview]
Message-ID: <87vdhx3h4g.fsf@frosties.localdomain> (raw)
In-Reply-To: <87639yue6y.fsf@mid.deneb.enyo.de> (Florian Weimer's message of "Thu, 29 Oct 2009 21:40:05 +0100")
Florian Weimer <fw@deneb.enyo.de> writes:
> * Goswin von Brederlow:
>
>> - The data is passed to libaio and needs to be kept alive and unmoved
>> as long as libaio knows it.
>
> It also has to be aligned to a 512-byte boundary, so you can use
> O_DIRECT. Linux does not support truely asynchronous I/O without
> O_DIRECT AFAIK, which rarely makes it worth the trouble.
True. But the libaio can provide a Aio.Buffer.make that returns an
aligned Bigarray (or string or whatever, currently a custom type).
If you write to files on a filesystem without O_DIRECT it will block
when submitting the requests till they have completed. Not sure what
happens on block devices without O_DIRECT.
My use case is for a Fuse Filesystem and writing to disks. O_DIRECT is
quite alright there. If you can't use O_DIRECT then you are left with
going multithreaded.
MfG
Goswin
next prev parent reply other threads:[~2009-10-29 23:38 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-28 13:54 Goswin von Brederlow
2009-10-28 14:16 ` Sylvain Le Gall
2009-10-28 15:00 ` [Caml-list] " Goswin von Brederlow
2009-10-28 15:17 ` Sylvain Le Gall
2009-10-28 17:57 ` [Caml-list] " Goswin von Brederlow
2009-10-28 18:19 ` Sylvain Le Gall
2009-10-28 21:05 ` [Caml-list] " Goswin von Brederlow
2009-10-28 21:26 ` Sylvain Le Gall
2009-10-28 22:48 ` [Caml-list] " blue storm
2009-10-29 9:50 ` Goswin von Brederlow
2009-10-29 10:34 ` Goswin von Brederlow
2009-10-29 12:20 ` Richard Jones
2009-10-29 17:07 ` Goswin von Brederlow
2009-10-30 20:30 ` Richard Jones
2009-11-01 15:11 ` Goswin von Brederlow
2009-11-01 19:57 ` Richard Jones
2009-11-02 16:11 ` Goswin von Brederlow
2009-11-02 16:33 ` Mauricio Fernandez
2009-11-02 20:27 ` Richard Jones
2009-11-03 13:18 ` Goswin von Brederlow
2009-11-02 20:48 ` Goswin von Brederlow
2009-10-29 20:40 ` Florian Weimer
2009-10-29 21:04 ` Gerd Stolpmann
2009-10-29 23:43 ` Goswin von Brederlow
2009-10-30 0:48 ` Gerd Stolpmann
2009-10-29 23:38 ` Goswin von Brederlow [this message]
2009-10-28 15:37 ` [Caml-list] " Olivier Andrieu
2009-10-28 16:05 ` Sylvain Le Gall
2009-10-28 15:43 ` [Caml-list] " Gerd Stolpmann
2009-10-28 16:06 ` Sylvain Le Gall
2009-10-28 18:09 ` [Caml-list] " Goswin von Brederlow
2009-10-28 17:09 ` Xavier Leroy
2009-10-28 19:05 ` Goswin von Brederlow
2009-10-29 17:05 ` Goswin von Brederlow
2009-10-29 18:42 ` Christophe TROESTLER
2009-10-29 19:03 ` Goswin von Brederlow
2009-10-29 18:48 ` Sylvain Le Gall
2009-10-29 23:25 ` [Caml-list] " Goswin von Brederlow
2009-11-03 17:16 Charles Forsyth
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