lkml.org 
[lkml]   [2006]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: What's in linux-2.6-block.git
>>>>> "Al" == Al Boldi <a1426z@gawab.com> writes:

Al> Jens Axboe wrote:
>> On Wed, Sep 13 2006, Al Boldi wrote:
>> > Jens Axboe wrote:
>> > > This lists the main features of the 'block' branch, which is bound for
>> > > Linus when 2.6.19 opens:
>> > >
>> > > - Splitting of request->flags into two parts:
>> > > - cmd type
>> > > - modified flags
>> > > Right now it's a bit of a mess, splitting this up invites a cleaner
>> > > usage and also enables us to implement generic "messages" passed on
>> > > the regular queue for the device.
>> > >
>> > > - Abstract out the request back merging and put it into the core io
>> > > scheduler layer. Cleans up all the io schedulers, and noop gets
>> > > merging for "free".
>> > >
>> > > - Abstract out the rbtree sorting. Gets rid of duplicated code in
>> > > as/cfq/deadline.
>> > >
>> > > - General shrinkage of the request structure.
>> > >
>> > > - Killing dynamic rq private structures in deadline/as/cfq. This
>> > > should speed up the io path somewhat, as we avoid allocating several
>> > > structures (struct request + scheduler private request) for each io
>> > > request.
>> > >
>> > > - meta data io logging for blktrace.
>> > >
>> > > - CFQ improvements.
>> > >
>> > > - Make the block layer configurable through Kconfig (David Howells).
>> > >
>> > > - Lots of cleanups.
>> >
>> > Does it also address the strange "max_sectors_kb<>192 causes a
>> > 50%-slowdown" problem?
>>
>> (remember to cc me/others when replying, I can easily miss lkml
>> messages for several days otherwise).
>>
>> It does not, the investigation of that is still pending I'm afraid. The
>> data is really puzzling, I'm inclined to think it's drive related. Are
>> you reproducing it just one box/drive, or on several?

Al> Several boxes, same drive.

Al> /dev/hda:

Al> ATA device, with non-removable media
Al> Model Number: WDC WD1200JB-00DUA0
Al> Serial Number: WD-WMACM1007651
Al> Firmware Revision: 65.13G65
Al> Standards:
Al> Supported: 6 5 4 3
Al> Likely used: 6

I've got a pair of drives which are very close in model type, and I
can run some non-destructive tests on them if you like to confirm
what's going on here if you like:

/dev/hde:

ATA device, with non-removable media
Model Number: WDC WD1200JB-00CRA1
Serial Number: WD-WMA8C4365875
Firmware Revision: 17.07W17
Standards:
Supported: 5 4 3
Likely used: 6
jfsnew:~> sudo hdparm -I /dev/hdg | head
/dev/hdg:

ATA device, with non-removable media
Model Number: WDC WD1200JB-00EVA0
Serial Number: WD-WMAEK2844058
Firmware Revision: 15.05R15
Standards:
Supported: 6 5 4
Likely used: 6


The drives have different defaul max_sectors too:

> cat /sys/block/hdg/queue/max_sectors_kb
512
> cat /sys/block/hde/queue/max_sectors_kb
128
Let me know your test method and I'll run it here and post the
results.

John
-
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: 2006-09-13 16:27    [from the cache]
©2003-2011 Jasper Spaans