[OpenAFS] ramdisk Problems under 2.6 kernel
ted creedon
tcreedon@easystreet.com
Wed, 6 Jul 2005 08:18:14 -0700
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It might be illustrative to use the MIT stress tests described at the 2005
Conference to benchmark various alternatives.
The presenter indicated that the test sources may be available in a few
months.
tedc
_____
From: openafs-info-admin@openafs.org [mailto:openafs-info-admin@openafs.org]
On Behalf Of ted creedon
Sent: Wednesday, July 06, 2005 7:47 AM
Cc: openafs-info@openafs.org
Subject: RE: [OpenAFS] ramdisk Problems under 2.6 kernel
Precisely what I do for a test system. Loopbacks work fine.
Any serious performance hits with loopback devices on /dev/shm?
tedc
_____
From: Sven Oehme [mailto:oehmes@de.ibm.com]
Sent: Wednesday, July 06, 2005 12:52 AM
To: ted creedon
Cc: openafs-info@openafs.org
Subject: RE: [OpenAFS] ramdisk Problems under 2.6 kernel
because you don't reach high enough throughput with memcache.
with memcache i am limited to around 25 mb/sec. with disk cache i reach 30
mb/sec which is the local drive.
with a formatted ramdisk as diskcache i get 50 - 60 mb/sec
so lets see if we can get a fix for /dev/shm ... because ramdisk is anyway
deprecated.
btw. the workaround is to create a file in /dev/shm with dd, format it ,
mount it as loopdevice :-)
Sven
"ted creedon" <tcreedon@easystreet.com>
Sent by: openafs-info-admin@openafs.org
05/07/2005 21:59
To
cc
<openafs-info@openafs.org>
Subject
RE: [OpenAFS] ramdisk Problems under 2.6 kernel
Why is that?
tedc
_____
From: openafs-info-admin@openafs.org [mailto:openafs-info-admin@openafs.org]
On Behalf Of Sven Oehme
Sent: Tuesday, July 05, 2005 10:08 AM
To: Ryan Underwood
Cc: openafs-info@openafs.org
Subject: Re: [OpenAFS] ramdisk Problems under 2.6 kernel
it's simple , it's to slow ..
Sven
Ryan Underwood <nemesis-lists@icequake.net>
Sent by: openafs-info-admin@openafs.org
05/07/2005 17:46
To
openafs-info@openafs.org
cc
Subject
Re: [OpenAFS] ramdisk Problems under 2.6 kernel
On Mon, Jul 04, 2005 at 11:38:14PM +0200, Sven Oehme wrote:
> Hi ,
>
> we have identified some Ramdisk Problems under 2.6 kernels compiled on
> i386
> has anybody ever tried using tmpfs for the cache disk ?
What about using -memcache instead?
--
Ryan Underwood, <nemesis@icequake.net>
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<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D093441515-06072005>It might be illustrative to use the MIT =
stress tests=20
described at the 2005 Conference to benchmark various=20
alternatives.</SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D093441515-06072005></SPAN></FONT> </DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D093441515-06072005>The presenter indicated that the test sources =
may be=20
available in a few months.</SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D093441515-06072005></SPAN></FONT> </DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D093441515-06072005>tedc</SPAN></FONT></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> openafs-info-admin@openafs.org =
[mailto:openafs-info-admin@openafs.org] <B>On Behalf Of </B>ted=20
creedon<BR><B>Sent:</B> Wednesday, July 06, 2005 7:47 AM<BR><B>Cc:</B>=20
openafs-info@openafs.org<BR><B>Subject:</B> RE: [OpenAFS] ramdisk =
Problems under=20
2.6 kernel<BR></FONT><BR></DIV>
<DIV></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>Precisely what I do for a test system. =
Loopbacks work=20
fine. </SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005></SPAN></FONT> </DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>Any serious performance hits with loopback =
devices on=20
/dev/shm?</SPAN></FONT></DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005></SPAN></FONT> </DIV>
<DIV dir=3Dltr align=3Dleft><FONT face=3DArial color=3D#0000ff =
size=3D2><SPAN=20
class=3D011214514-06072005>tedc</SPAN></FONT></DIV><BR>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr align=3Dleft>
<HR tabIndex=3D-1>
<FONT face=3DTahoma size=3D2><B>From:</B> Sven Oehme =
[mailto:oehmes@de.ibm.com]=20
<BR><B>Sent:</B> Wednesday, July 06, 2005 12:52 AM<BR><B>To:</B> ted=20
creedon<BR><B>Cc:</B> openafs-info@openafs.org<BR><B>Subject:</B> RE: =
[OpenAFS]=20
ramdisk Problems under 2.6 kernel<BR></FONT><BR></DIV>
<DIV></DIV><BR><FONT face=3Dsans-serif size=3D2>because you don't reach =
high enough=20
throughput with memcache. </FONT><BR><FONT face=3Dsans-serif =
size=3D2>with memcache=20
i am limited to around 25 mb/sec. with disk cache i reach 30 mb/sec =
which is the=20
local drive.</FONT> <BR><FONT face=3Dsans-serif size=3D2>with a =
formatted ramdisk as=20
diskcache i get 50 - 60 mb/sec</FONT> <BR><FONT face=3Dsans-serif =
size=3D2>so lets=20
see if we can get a fix for /dev/shm ... because ramdisk is anyway =
deprecated.=20
</FONT><BR><FONT face=3Dsans-serif size=3D2>btw. the workaround is to =
create a file=20
in /dev/shm with dd, format it , mount it as loopdevice :-)</FONT> =
<BR><BR><FONT=20
face=3Dsans-serif size=3D2>Sven</FONT> <BR><BR><BR><BR>
<TABLE width=3D"100%">
<TBODY>
<TR vAlign=3Dtop>
<TD width=3D"40%"><FONT face=3Dsans-serif size=3D1><B>"ted creedon"=20
<tcreedon@easystreet.com></B> </FONT><BR><FONT =
face=3Dsans-serif=20
size=3D1>Sent by: openafs-info-admin@openafs.org</FONT>=20
<P><FONT face=3Dsans-serif size=3D1>05/07/2005 21:59</FONT> </P>
<TD width=3D"59%">
<TABLE width=3D"100%">
<TBODY>
<TR>
<TD>
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>To</FONT></DIV>
<TD vAlign=3Dtop>
<TR>
<TD>
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>cc</FONT></DIV>
<TD vAlign=3Dtop><FONT face=3Dsans-serif=20
size=3D1><openafs-info@openafs.org></FONT>=20
<TR>
<TD>
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>Subject</FONT></DIV>
<TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1>RE: =
[OpenAFS] ramdisk=20
Problems under 2.6 =
kernel</FONT></TD></TR></TBODY></TABLE><BR>
<TABLE>
<TBODY>
<TR vAlign=3Dtop>
<TD>
=
<TD></TD></TR></TBODY></TABLE><BR></TD></TR></TBODY></TABLE><BR><BR><BR><=
FONT=20
face=3DArial color=3Dblue size=3D2>Why is that?</FONT> <BR><FONT =
size=3D3> </FONT>=20
<BR><FONT face=3DArial color=3Dblue size=3D2>tedc</FONT> <BR><BR>
<HR>
<FONT face=3DTahoma size=3D2><B>From:</B> openafs-info-admin@openafs.org =
[mailto:openafs-info-admin@openafs.org] <B>On Behalf Of </B>Sven=20
Oehme<B><BR>Sent:</B> Tuesday, July 05, 2005 10:08 AM<B><BR>To:</B> Ryan =
Underwood<B><BR>Cc:</B> openafs-info@openafs.org<B><BR>Subject:</B> Re:=20
[OpenAFS] ramdisk Problems under 2.6 kernel</FONT><FONT=20
size=3D3><BR></FONT><BR><FONT face=3Dsans-serif size=3D2><BR>it's simple =
, it's to=20
slow ..</FONT><FONT size=3D3> <BR></FONT><FONT face=3Dsans-serif=20
size=3D2><BR>Sven</FONT><FONT size=3D3><BR><BR><BR></FONT>
<TABLE width=3D"100%">
<TBODY>
<TR vAlign=3Dtop>
<TD width=3D"44%"><FONT face=3Dsans-serif size=3D1><B>Ryan Underwood =
<nemesis-lists@icequake.net></B> <BR>Sent by:=20
openafs-info-admin@openafs.org</FONT><FONT size=3D3> </FONT>
<P><FONT face=3Dsans-serif size=3D1>05/07/2005 17:46</FONT><FONT =
size=3D3>=20
</FONT></P>
<TD width=3D"55%"><BR>
<TABLE width=3D"100%">
<TBODY>
<TR>
<TD width=3D"18%">
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>To</FONT></DIV>
<TD vAlign=3Dtop width=3D"81%"><FONT face=3Dsans-serif=20
size=3D1>openafs-info@openafs.org</FONT><FONT size=3D3> =
</FONT>
<TR>
<TD>
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>cc</FONT></DIV>
<TD vAlign=3Dtop>
<TR>
<TD>
<DIV align=3Dright><FONT face=3Dsans-serif =
size=3D1>Subject</FONT></DIV>
<TD vAlign=3Dtop><FONT face=3Dsans-serif size=3D1>Re: =
[OpenAFS] ramdisk=20
Problems under 2.6 =
kernel</FONT></TD></TR></TBODY></TABLE><BR><BR>
<TABLE width=3D"100%">
<TBODY>
<TR vAlign=3Dtop>
<TD width=3D"49%">
<TD=20
width=3D"50%"></TD></TR></TBODY></TABLE><BR></TD></TR></TBODY></TABLE><BR=
><FONT=20
size=3D3><BR><BR></FONT><FONT size=3D2><TT><BR><BR>On Mon, Jul 04, 2005 =
at=20
11:38:14PM +0200, Sven Oehme wrote:<BR>> Hi ,<BR>> =
<BR>>=20
we have identified some Ramdisk Problems under 2.6 kernels =
compiled=20
on<BR>> i386<BR>> has anybody ever tried =
using=20
tmpfs for the cache disk ?<BR><BR>What about using -memcache =
instead?<BR><BR>--=20
<BR>Ryan Underwood,=20
<nemesis@icequake.net><BR>_________________________________________=
______<BR>OpenAFS-info=20
mailing=20
list<BR>OpenAFS-info@openafs.org<BR>https://lists.openafs.org/mailman/lis=
tinfo/openafs-info</TT></FONT><FONT=20
size=3D3><BR></FONT><BR></BODY></HTML>
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