lkml.org 
[lkml]   [2008]   [Aug]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Opteron Rev E has a bug ... a locked instruction doesn't act as a read-acquire barrier
On Mon, 4 Aug 2008 15:56:05 +0200, Arkadiusz Miskiewicz wrote:
>On Monday 04 August 2008, Mikael Pettersson wrote:
>> Arkadiusz Miskiewicz writes:
>> > Hello,
>> >
>> > http://google-perftools.googlecode.com/svn-history/r48/trunk/src/base/=
>at
>> >omicops-internals-x86.cc says
>> >
>> > " // Opteron Rev E has a bug in which on very rare occasions a locked
>> > // instruction doesn't act as a read-acquire barrier if followed by a
>> > // non-locked read-modify-write instruction. Rev F has this bug in
>> > // pre-release versions, but not in versions released to customers,
>> > // so we test only for Rev E, which is family 15, model 32..63
>> > inclusive. if (strcmp(vendor, "AuthenticAMD") =3D=3D 0 && // AMD
>> > family =3D=3D 15 &&
>> > 32 <=3D model && model <=3D 63) {
>> > AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug =3D true;
>> > } else {
>> > AtomicOps_Internalx86CPUFeatures.has_amd_lock_mb_bug =3D false;
>> > }
>> > "
>> >
>> > does kernel have quirk/workaround for this? I'm looking at
>> > arch/x86/kernel/cpu but I don't see workaround related to this (possib=
>ly
>> > I'm overlooking).
>>
>> I can find no reference to this alleged RevE erratum in the
>> Athlon64/Opteron revision guide (25759.pdf).
>>
>> But if this bug is real then we need to know about it. Could
>> you ask the author of the code you quoted above to clarify?
>
>Got answer, opensolaris has some workarounds for this bug I still don't kno=
>w=20
>which errata # is that:
>
>http://groups.google.com/group/google-perftools/browse_thread/thread/3d1b78=
>d4a9db8c6e
>
>btw. I got info about this bug after hiting this problem:=20
>http://bugs.mysql.com/bug.php?id=3D26081

Thanks, found the Solaris code in question and the mysql discussion.
I'll dig deeper tomorrow.

/Mikael


\
 
 \ /
  Last update: 2008-08-04 16:57    [W:0.281 / U:0.300 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site