diff options
| author | Dapeng Mi <dapeng1.mi@linux.intel.com> | 2025-09-19 10:16:58 +0800 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2025-10-02 15:31:39 -0300 |
| commit | c1afca106e16fbbf9508b3770e6ab1c2f7993ea1 (patch) | |
| tree | 929030db36546a68d11ca4dde8919e53549d8b43 /tools/perf/builtin-kvm.c | |
| parent | 0f53264d714ae7db2a827b3483418f0288fa953f (diff) | |
perf tools kvm: Use "cycles" to sample guest for "kvm record" on Intel
After KVM supports PEBS for guest on Intel platforms
(https://lore.kernel.org/all/20220411101946.20262-1-likexu@tencent.com/),
host loses the capability to sample guest with PEBS since all PEBS related
MSRs are switched to guest value after vm-entry, like IA32_DS_AREA MSR is
switched to guest GVA at vm-entry. This would lead to "perf kvm record"
fails to sample guest on Intel platforms since "cycles:P" event is used to
sample guest by default as below case shows.
sudo perf kvm record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.787 MB perf.data.guest ]
So to ensure guest record can be sampled successfully, use "cycles"
instead of "cycles:P" to sample guest record by default on Intel
platforms. With this patch, the guest record can be sampled
successfully.
sudo perf kvm record -a
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.783 MB perf.data.guest (23 samples) ]
Fixes: cf8e55fe50df0c02 ("KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64")
Reported-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Like Xu <likexu@tencent.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-kvm.c')
| -rw-r--r-- | tools/perf/builtin-kvm.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c index d297a7b2c088..c0d62add4996 100644 --- a/tools/perf/builtin-kvm.c +++ b/tools/perf/builtin-kvm.c @@ -1636,16 +1636,6 @@ exit: return ret; } -#define STRDUP_FAIL_EXIT(s) \ - ({ char *_p; \ - _p = strdup(s); \ - if (!_p) { \ - ret = -ENOMEM; \ - goto EXIT; \ - } \ - _p; \ - }) - int __weak setup_kvm_events_tp(struct perf_kvm_stat *kvm __maybe_unused) { return 0; |