lkml.org 
[lkml]   [2011]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/8] readahead: make default readahead size a kernel parameter


On 11/28/2011 03:39 AM, Wu Fengguang wrote:
> On Fri, Nov 25, 2011 at 08:36:33AM +0800, Dave Chinner wrote:
>> On Thu, Nov 24, 2011 at 11:28:22PM +0100, Jan Kara wrote:
>>> On Mon 21-11-11 19:35:40, Wu Fengguang wrote:
>>>> On Mon, Nov 21, 2011 at 06:01:37PM +0800, Christoph Hellwig wrote:
>>>>> On Mon, Nov 21, 2011 at 05:18:21PM +0800, Wu Fengguang wrote:
>>>>>> From: Nikanth Karthikesan<knikanth@suse.de>
>>>>>>
[...]

>>
>> And one that has already been in use for exactly this purpose for
>> years. Indeed, it's far more flexible because you can give different
>> types of devices different default readahead settings quite easily,
>> and it you can set different defaults for just about any tunable
>> parameter (e.g. readahead, ctq depth, max IO sizes, etc) in the same
>> way.
>
> I'm interested in this usage, too. Would you share some of your rules?
>

FYI - This is an example of a rules Suse delivers in SLES @ s390 for a
while now. With little modifications it could be used for all Dave
mentioned above.

cat /etc/udev/rules.d/60-readahead.rules
#



# Rules to set an increased default max readahead size for s390 disk
devices


# This file should be installed in /etc/udev/rules.d



#







SUBSYSTEM!="block", GOTO="ra_end"







ACTION!="add", GOTO="ra_end"



# on device add set initial readahead to 512 (instead of in kernel 128)



KERNEL=="sd*[!0-9]", ATTR{queue/read_ahead_kb}="512"



KERNEL=="dasd*[!0-9]", ATTR{queue/read_ahead_kb}="512"




LABEL="ra_end"

--

Grüsse / regards, Christian Ehrhardt
IBM Linux Technology Center, System z Linux Performance

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

\
 
 \ /
  Last update: 2011-11-30 14:07    [W:0.103 / U:1.784 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site