Messages in this thread |  | | | Date | Fri, 29 Apr 2011 20:17:24 +0300 | | Subject | Re: re-enable Nehalem raw Offcore-Events support | | From | Pekka Enberg <> |
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Hi Vince,
On Fri, Apr 29, 2011 at 6:04 PM, Vince Weaver <vweaver1@eecs.utk.edu> wrote: > Hello Linus > > can you revert the commit b52c55c6a25e4515b5e075a989ff346fc251ed09 > > This removed functionality from perf_events that allowed raw event access > for OFFCORE_EVENTS type events on Nehalem and Westmere cpus. > > To be fair, this is not technically a regression as the feature was only > (finally!) added in the 2.6.39 merge window. However this is a useful > feature and many tools (including the PAPI performance counter library > that I work on) had added support for it in anticipation of the 2.6.39 > release. > > Ingo's reasons for removing the feature seem to boil down to > 1. "perf" doesn't use the functionality, and any other userspace > program that uses the perf_events syscalls don't matter > 2. Users are too stupid to use the raw functionality properly; > we should only allow a kernel-developer-approved small subset > of the features provided by the CPU as described in the intel > developers manuals. > > #2 seems like a gross misinterpretation of the whole "Linux gives you > enough rope to shoot yourself in the foot" policy from days passed, but > maybe things have moved on.
That's a gross misrepresentation of what Ingo has been saying on LKML. Really, learn to work with relevant maintainers before you ask Linus to revert something.
Pekka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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