From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
peterz@infradead.org, acme@kernel.org
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Suzuki Poulose <suzuki.poulose@arm.com>,
James Clark <james.clark@arm.com>, Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH V4 01/10] perf: Add irq and exception return branch types
Date: Tue, 15 Mar 2022 11:05:07 +0530 [thread overview]
Message-ID: <20220315053516.431515-2-anshuman.khandual@arm.com> (raw)
In-Reply-To: <20220315053516.431515-1-anshuman.khandual@arm.com>
This expands generic branch type classification by adding two more entries
there in i.e irq and exception return. Also updates the x86 implementation
to process X86_BR_IRET and X86_BR_IRQ records as appropriate. This changes
branch types reported to user space on x86 platform but it should not be a
problem. The possible scenarios and impacts are enumerated here.
--------------------------------------------------------------------------
| kernel | perf tool | Impact |
--------------------------------------------------------------------------
| old | old | Works as before |
--------------------------------------------------------------------------
| old | new | PERF_BR_UNKNOWN is processed |
--------------------------------------------------------------------------
| new | old | PERF_BR_ERET/IRQ are blocked via old PERF_BR_MAX |
--------------------------------------------------------------------------
| new | new | PERF_BR_ERET/IRQ are recognized |
--------------------------------------------------------------------------
When PERF_BR_ERET/IRQ are blocked via old PERF_BR_MAX (new kernel with old
perf tool) the user space might throw up an warning complaining about some
unrecognized branch types being reported, but it is expected. PERF_BR_ERET
and PERF_BR_IRQ branch types will be used for BRBE implementation on arm64
platform.
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-perf-users@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
arch/x86/events/intel/lbr.c | 4 ++--
include/uapi/linux/perf_event.h | 2 ++
2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 669c2be14784..fe1742c4ca49 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1329,10 +1329,10 @@ static int branch_map[X86_BR_TYPE_MAP_MAX] = {
PERF_BR_SYSCALL, /* X86_BR_SYSCALL */
PERF_BR_SYSRET, /* X86_BR_SYSRET */
PERF_BR_UNKNOWN, /* X86_BR_INT */
- PERF_BR_UNKNOWN, /* X86_BR_IRET */
+ PERF_BR_ERET, /* X86_BR_IRET */
PERF_BR_COND, /* X86_BR_JCC */
PERF_BR_UNCOND, /* X86_BR_JMP */
- PERF_BR_UNKNOWN, /* X86_BR_IRQ */
+ PERF_BR_IRQ, /* X86_BR_IRQ */
PERF_BR_IND_CALL, /* X86_BR_IND_CALL */
PERF_BR_UNKNOWN, /* X86_BR_ABORT */
PERF_BR_UNKNOWN, /* X86_BR_IN_TX */
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 82858b697c05..d37629dbad72 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -251,6 +251,8 @@ enum {
PERF_BR_SYSRET = 8, /* syscall return */
PERF_BR_COND_CALL = 9, /* conditional function call */
PERF_BR_COND_RET = 10, /* conditional function return */
+ PERF_BR_ERET = 11, /* exception return */
+ PERF_BR_IRQ = 12, /* irq */
PERF_BR_MAX,
};
--
2.25.1
next prev parent reply other threads:[~2022-03-15 5:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-15 5:35 [PATCH V4 00/10] perf: Expand perf_branch_entry Anshuman Khandual
2022-03-15 5:35 ` Anshuman Khandual [this message]
2022-03-15 5:35 ` [PATCH V4 02/10] perf: Add system error and not in transaction branch types Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 03/10] perf: Extend branch type classification Anshuman Khandual
2022-03-15 11:22 ` Peter Zijlstra
2022-03-15 13:06 ` Robin Murphy
2022-03-16 12:20 ` Peter Zijlstra
2022-03-17 5:41 ` Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 04/10] perf: Capture branch privilege information Anshuman Khandual
2022-03-16 17:26 ` James Clark
2022-03-15 5:35 ` [PATCH V4 05/10] perf: Add PERF_BR_NEW_ARCH_[N] map for BRBE on arm64 platform Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 06/10] perf/tools: Add irq and exception return branch types Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 07/10] perf/tools: Add system error and not in transaction " Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 08/10] perf/tools: Extend branch type classification Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 09/10] perf/tools: Add branch privilege information request flag Anshuman Khandual
2022-03-15 5:35 ` [PATCH V4 10/10] perf/tools: Add PERF_BR_NEW_ARCH_[N] map for BRBE on arm64 platform Anshuman Khandual
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