Stephane Eranian wrote:
Will, On Fri, Jun 23, 2006 at 05:13:47PM -0400, William Cohen wrote:Hi Stephane, Some quick questions about the current perfmon code. The athlon has very similar hw to the amd64 and there is now 32-bit x86-64 support. Wouldn't it make sense to move perfmon_amd.c to i386 and have it work in the same way as perfmon_p4.c does currently for p4 and em64t?Does Athlon have 4 counters as well. I don't have the HW so I cannot really test. I suspect they are similar. If you have HW and you can test, I don't have a problem.
I have an Athlon machine in the office that I can test this change out on and send you a diff.
Could the 32-bit and 64-bit code be combined in a manner similar to oprofile and avoid duplication between perfmon_em64t_pebs.c and perfmon_p4_pebs.c? pfm_{p4|em64}_ds_area and pfm_{p4|em64t}_pebs_sample_entry have differences due to the upgrade from 32 to 64 bit values.You have several issues here: - the 64-bit version has 8 more reigsters int the PEBS entry - the PEBS entry uses 32 or 64 bitfields depending on data model - the ds_area uses 32 or 64 bits depending on the data model except for the threshold valueNow remember that on on EM64T we also support 32-bit (i386) binaries. With an EM64T kernel you would have the 64-bit PEBS format. With the same UUID if would satisfya i386 binary and this is wrong because they would not match the definition of the PEBS entry. We need to keep the PEBS 32 and 64-bit format UUIDs different. At the source code level, you would need to ifdef __x86_64__ and __i386__ to switch struct definition and UUID. That's doable but is this clean?
Certainly given the differences in the pebs elements there will need to unique names for each. It was just a thought to factor out the similar code.
There is support to handle amd64 hardware running on 32-bit kernel. Has someone verified that the em64t processor generate 32-bit compatible entries when running in 32-bit mode? Or does it always write out 64-bit style PEBS entries?
Why isn't Intel family 0xf model 3 not supported? Model 1,2, 4, and 5 are supported. Model 3 Pentium4 isn't that different is it?I have not looked at this. I don't have a lot of P4 HW. I think that all family 15 uses the same PMU. Could someone confirm this?
A NC State University professor mentioned that the ommission of model 3 was a problem because his machine were model 3. I suggested the addition of case for model 3 processors to get him going on that.
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