Re: [Xen-devel] [PATCH] Oprofile patch for 2.6.27 tree. Fix collisionbetween Xen and Cell processor escape codes

[Jean Guyader <jean.guyader@xxxxxxxxx>]

2009/6/25 Steven Smith <steven.smith@xxxxxxxxxx>:
>> > I'm a little confused by this: Upstream oprofile 0.9.4 has
>> > the same workaround implemented on the user mode side of
>> > things, so adjusting this in the kernel now would make the
>> > kernel incompatible with that and future versions. Jan
>>   The fact that oprofile user level code has the same workaround
>>   is exactly the reason for this patch.
>>   We need the same code values in the kernel and in the user level tools.
>>   Right now the kernel generates code 13 for DOMAIN_SWITCH_CODE
>>   in x86 and Oprofile daemon complains that there is no such code.
>>   (it expects code 11 for that).
>>
>>   However, your question made me look at Oprofile 0.9.4 and I noticed
>>   this workaround changed slightly from 0.9.3 to 0.9.4.
>>   The new code checks for powerpc while 0.9.3 checked for
>>   x96 and ia64. So we need a slightly different patch.
>>
>>   Please use the new attached patch instead of the original one.
> Ian: Can you apply this to the 2.6.27 tree, please?  I'll pull it
> through to NC2 from there.
>

I've applied this patch on the XCI 2.6.27 tree, it should be available soon.

Thanks,
Jean

>
>>     Fix OProfile escape code collision between Xenoprof's
>>     DOMAIN_SWITCH_CODE (in use on x86 and ia64) and Cell's
>>     SPU_PROFILING_CODE(in use with Power).
>>
>>     Signed-off-by: Jose Renato Santos <jsantos@xxxxxxxxxx>
>>
>> diff --git a/include/linux/oprofile.h b/include/linux/oprofile.h
>> index bb8a349..8863734 100644
>> --- a/include/linux/oprofile.h
>> +++ b/include/linux/oprofile.h
>> @@ -37,9 +37,18 @@
>>  #define TRACE_BEGIN_CODE             8
>>  #define TRACE_END_CODE                       9
>>  #define XEN_ENTER_SWITCH_CODE                10
>> +/*
>> + * Ugly work-around for the unfortunate collision between Xenoprof's
>> + * DOMAIN_SWITCH_CODE (in use on x86 and ia64) and Cell's SPU_PROFILING_CODE
>> + * (in use with Power):
>> + */
>> +#ifdef CONFIG_PPC
>>  #define SPU_PROFILING_CODE           11
>>  #define SPU_CTX_SWITCH_CODE          12
>>  #define DOMAIN_SWITCH_CODE           13
>> +#else
>> +#define DOMAIN_SWITCH_CODE           11
>> +#endif
>>
>>  struct super_block;
>>  struct dentry;
>>
>>
>
>
>
>
>> > >>> "Santos, Jose Renato G" <joserenato.santos@xxxxxx> 23.06.09 20:13
>> > >>> >>>
>> >
>> > Steven
>> >
>> > This is a fix to enable Oprofile to work on the netchannel2
>> > 2.6.27 tree.
>> >
>> > This is to address a collision for escape codes used to
>> > represent domain switches in Xen and CPU switches in cell
>> > processors which were developed in parallel and used the same code.
>> >
>> > There was a discussion on the Oprofile mailing list a while
>> > ago and it was decided that we would use different Oprofile
>> > codes for x86 and ia64 archs (which are the only ones that
>> > support Oprofile in Xen) in order to preserve backward
>> > compatibility for users.
>> >
>> > The Oprofile user level tools expect different escape codes
>> > depending on the architecture. We need to make sure the
>> > kernel generates compatible escape codes.
>> >
>> > I think this should be also pushed to the 2.6.27 XenClient tree.
>> >
>> > Thanks
>> >
>> > Renato
>> >
>> >
>
>
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