Kan Liang 9f3de72a0c perf/x86/intel/ds: Unconditionally drain PEBS DS when changing PEBS_DATA_CFG ... The PEBS kernel warnings can still be observed with the below case. when the below commands are running in parallel for a while. while true; do perf record --no-buildid -a --intr-regs=AX \ -e cpu/event=0xd0,umask=0x81/pp \ -c 10003 -o /dev/null ./triad; done & while true; do perf record -e 'cpu/mem-loads,ldlat=3/uP' -W -d -- ./dtlb done The commit b752ea0c28 ("perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG") intends to flush the entire PEBS buffer before the hardware is reprogrammed. However, it fails in the above case. The first perf command utilizes the large PEBS, while the second perf command only utilizes a single PEBS. When the second perf event is added, only the n_pebs++. The intel_pmu_pebs_enable() is invoked after intel_pmu_pebs_add(). So the cpuc->n_pebs == cpuc->n_large_pebs check in the intel_pmu_drain_large_pebs() fails. The PEBS DS is not flushed. The new PEBS event should not be taken into account when flushing the existing PEBS DS. The check is unnecessary here. Before the hardware is reprogrammed, all the stale records must be drained unconditionally. For single PEBS or PEBS-vi-pt, the DS must be empty. The drain_pebs() can handle the empty case. There is no harm to unconditionally drain the PEBS DS. Fixes: b752ea0c28 ("perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG") Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20241119135504.1463839-2-kan.liang@linux.intel.com		2024-12-02 12:01:33 +01:00
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amd	perf/x86/amd/uncore: Avoid a false positive warning about snprintf truncation in amd_uncore_umc_ctx_init	2024-11-11 11:49:47 +01:00
intel	perf/x86/intel/ds: Unconditionally drain PEBS DS when changing PEBS_DATA_CFG	2024-12-02 12:01:33 +01:00
zhaoxin	perf/x86: Support counter mask	2024-07-04 16:00:36 +02:00
core.c	perf/core: Correct perf sampling with guest VMs	2024-11-14 10:40:01 +01:00
Kconfig	perf/x86/Kconfig: Fix indentation in the Kconfig file	2022-05-25 15:54:26 +02:00
Makefile	perf/x86: Move branch classifier	2022-08-27 00:05:44 +02:00
msr.c	perf/x86/msr: Switch to new Intel CPU model defines	2024-04-29 10:31:04 +02:00
perf_event_flags.h	perf/x86/intel: Support branch counters logging	2023-10-27 15:05:11 +02:00
perf_event.h	perf/x86/intel: Add PMU support for ArrowLake-H	2024-10-07 09:28:43 +02:00
probe.c	perf/x86/rapl: Add msr mask support	2021-02-10 14:44:54 +01:00
probe.h	perf/x86/rapl: Add msr mask support	2021-02-10 14:44:54 +01:00
rapl.c	perf/x86/rapl: Clean up cpumask and hotplug	2024-10-30 22:42:19 +01:00
utils.c	perf/x86/lbr: Filter vsyscall addresses	2023-10-08 12:25:18 +02:00