Messages in this thread | | | Date | Tue, 15 Apr 2008 16:53:33 +0200 | From | "stephane eranian" <> | Subject | perfmon and Markus' DS/BTS/PEBS interface |
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Hello,
Over the last few weeks, I have been working with Markus Metzger from Intel to add support for Precise Event-Based Sampling (PEBS) to his ds.c/ds.h interface. I thought this could help simplify some of the perfmon code.
The current ds.h/ds.c code in 2.6.25-rc8 does not yet have PEBS support. It only has Branch Trace Stack (BTS) support. Markus developed the PEBS extension. It is fairly simple and small. I strongly believe it should be included in mainline very soon. To verify that it would work correctly with perfmon, I did the experiment last week.
I just wanted to report to this list that I have now successfully connected perfmon to ds.h. It allows some more simplifications in perfmon. In particular, it does not have to manage the DS_AREA MSR on context switch anymore. Similarly, the layout differences between Pentium 4 and Intel Core processors for the DS_AREA are now hidden, meaning more code can be factorized. At the user level, it also simplifies the interface as we do not have to expose as much information as we used to (e.g., DS_AREA is not exposed anymore).
Overall I am satisfied with this patch and I recommend you accept the extended ds.h/ds.c interface.
Thanks.
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