Messages in this thread |  | | Date | Thu, 23 Sep 2021 22:40:48 +0800 | From | Leo Yan <> | Subject | Re: [PATCH 4/5] perf arm-spe: Implement find_snapshot callback |
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On Thu, Sep 23, 2021 at 09:50:16PM +0800, Leo Yan wrote:
[...]
> > @@ -336,6 +480,7 @@ struct auxtrace_record *arm_spe_recording_init(int *err, > > sper->itr.pmu = arm_spe_pmu; > > sper->itr.snapshot_start = arm_spe_snapshot_start; > > sper->itr.snapshot_finish = arm_spe_snapshot_finish; > > + sper->itr.find_snapshot = arm_spe_find_snapshot; > > If I understand correctly, this patch copies the code from cs-etm for > snapshot handling. About 2 months ago, we removed the Arm cs-etm's > specific snapshot callback function and directly use perf's function > __auxtrace_mmap__read() to handle 'head' and 'tail' pointers. Please > see the commit for details: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2f01c200d4405c4562e45e8bb4de44a5ce37b217 > > Before I review more details for snapshot enabling in patches 03 and > 04, could you confirm if Arm SPE can use the same way with cs-etm for > snapshot handling? From my understanding, this is a better way to > handle AUX buffer's 'head' and 'tail'.
In other words, if we can only apply patch 03 and can pass the testing in patch 05, then it would be a very neat implementation.
I will try to verify these patches and will get back result.
Thanks, Leo
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