[tip: perf/urgent] perf/x86/amd/core: Define a proper ref-cycles event for Zen 4 and later

From: tip-bot2 for Sandipan Das
Date: Mon Mar 25 2024 - 10:25:51 EST


The following commit has been merged into the perf/urgent branch of tip:

Commit-ID: 563bdbac10e5abe49c332b380fedd8ee7dc72b05
Gitweb: https://git.kernel.org/tip/563bdbac10e5abe49c332b380fedd8ee7dc72b05
Author: Sandipan Das <sandipan.das@xxxxxxx>
AuthorDate: Mon, 25 Mar 2024 13:17:54 +05:30
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 25 Mar 2024 11:19:04 +01:00

perf/x86/amd/core: Define a proper ref-cycles event for Zen 4 and later

Add the "ref-cycles" event for AMD processors based on Zen 4 and later
microarchitectures. The backing event is based on PMCx120 which counts
cycles not in halt state in P0 frequency (same as MPERF).

Signed-off-by: Sandipan Das <sandipan.das@xxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/089155f19f7c7e65aeb1caa727a882e2ca9b8b04.1711352180.git.sandipan.das@xxxxxxx
---
arch/x86/events/amd/core.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index af8add6..985ef3b 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -273,8 +273,23 @@ static const u64 amd_zen2_perfmon_event_map[PERF_COUNT_HW_MAX] =
[PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x00a9,
};

+static const u64 amd_zen4_perfmon_event_map[PERF_COUNT_HW_MAX] =
+{
+ [PERF_COUNT_HW_CPU_CYCLES] = 0x0076,
+ [PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0,
+ [PERF_COUNT_HW_CACHE_REFERENCES] = 0xff60,
+ [PERF_COUNT_HW_CACHE_MISSES] = 0x0964,
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x00c2,
+ [PERF_COUNT_HW_BRANCH_MISSES] = 0x00c3,
+ [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x00a9,
+ [PERF_COUNT_HW_REF_CPU_CYCLES] = 0x100000120,
+};
+
static u64 amd_pmu_event_map(int hw_event)
{
+ if (cpu_feature_enabled(X86_FEATURE_ZEN4) || boot_cpu_data.x86 >= 0x1a)
+ return amd_zen4_perfmon_event_map[hw_event];
+
if (cpu_feature_enabled(X86_FEATURE_ZEN2) || boot_cpu_data.x86 >= 0x19)
return amd_zen2_perfmon_event_map[hw_event];