[PATCH 0/4] tools perf: Add branch speculation info

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* [PATCH 0/4] tools perf: Add branch speculation info
@ 2022-08-11 12:46 Sandipan Das
  2022-08-11 12:46 ` [PATCH 1/4] tools headers uapi: Sync perf_event.h with kernel sources Sandipan Das
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-11 12:46 UTC (permalink / raw)
  To: linux-kernel, linux-perf-users, x86
  Cc: peterz, bp, acme, namhyung, jolsa, tglx, mingo, mark.rutland,
	alexander.shishkin, dave.hansen, like.xu.linux, eranian,
	ananth.narayan, ravi.bangoria, santosh.shukla, sandipan.das

AMD Last Branch Record Extension Version 2 (LbrExtV2) provides branch
speculation information and the perf UAPI is extended to provide this in a
generic manner. Update the tools headers and perf tool to be able to show
this additional information.

The LbrExtV2 enablement and UAPI changes can be found at:
https://lore.kernel.org/all/cover.1660211399.git.sandipan.das@amd.com/

Sandipan Das (4):
  tools headers uapi: Sync perf_event.h with kernel sources
  tools headers x86: Sync msr-index.h with kernel sources
  perf script: Show branch speculation info
  perf session: Show branch speculation info in raw dump

 tools/arch/x86/include/asm/msr-index.h |  5 +++++
 tools/include/uapi/linux/perf_event.h  | 15 ++++++++++++++-
 tools/perf/builtin-script.c            |  5 +++--
 tools/perf/util/branch.c               | 15 +++++++++++++++
 tools/perf/util/branch.h               |  5 ++++-
 tools/perf/util/evsel.c                |  9 ++++++---
 tools/perf/util/session.c              |  5 +++--
 7 files changed, 50 insertions(+), 9 deletions(-)

-- 
2.34.1


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 1/4] tools headers uapi: Sync perf_event.h with kernel sources
  2022-08-11 12:46 [PATCH 0/4] tools perf: Add branch speculation info Sandipan Das
@ 2022-08-11 12:46 ` Sandipan Das
  2022-08-11 12:46 ` [PATCH 2/4] tools headers x86: Sync msr-index.h " Sandipan Das
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-11 12:46 UTC (permalink / raw)
  To: linux-kernel, linux-perf-users, x86
  Cc: peterz, bp, acme, namhyung, jolsa, tglx, mingo, mark.rutland,
	alexander.shishkin, dave.hansen, like.xu.linux, eranian,
	ananth.narayan, ravi.bangoria, santosh.shukla, sandipan.das

Sync perf_event.h with the kernel sources by adding the new "spec" bitfield
to branch entries.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 tools/include/uapi/linux/perf_event.h | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index 4653834f078f..3afda2dc84dd 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -256,6 +256,17 @@ enum {
 	PERF_BR_MAX,
 };
 
+/*
+ * Common branch speculation outcome classification
+ */
+enum {
+	PERF_BR_SPEC_NA			= 0,	/* Not available */
+	PERF_BR_SPEC_WRONG_PATH		= 1,	/* Speculative but on wrong path */
+	PERF_BR_NON_SPEC_CORRECT_PATH	= 2,	/* Non-speculative but on correct path */
+	PERF_BR_SPEC_CORRECT_PATH	= 3,	/* Speculative and on correct path */
+	PERF_BR_SPEC_MAX,
+};
+
 #define PERF_SAMPLE_BRANCH_PLM_ALL \
 	(PERF_SAMPLE_BRANCH_USER|\
 	 PERF_SAMPLE_BRANCH_KERNEL|\
@@ -1360,6 +1371,7 @@ union perf_mem_data_src {
  *     abort: aborting a hardware transaction
  *    cycles: cycles from last branch (or 0 if not supported)
  *      type: branch type
+ *      spec: branch speculation info (or 0 if not supported)
  */
 struct perf_branch_entry {
 	__u64	from;
@@ -1370,7 +1382,8 @@ struct perf_branch_entry {
 		abort:1,    /* transaction abort */
 		cycles:16,  /* cycle count to last branch */
 		type:4,     /* branch type */
-		reserved:40;
+		spec:2,     /* branch speculation info */
+		reserved:38;
 };
 
 union perf_sample_weight {
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-11 12:46 [PATCH 0/4] tools perf: Add branch speculation info Sandipan Das
  2022-08-11 12:46 ` [PATCH 1/4] tools headers uapi: Sync perf_event.h with kernel sources Sandipan Das
@ 2022-08-11 12:46 ` Sandipan Das
  2022-08-12  8:33   ` Jiri Olsa
  2022-08-11 12:46 ` [PATCH 3/4] perf script: Show branch speculation info Sandipan Das
  2022-08-11 12:46 ` [PATCH 4/4] perf session: Show branch speculation info in raw dump Sandipan Das
  3 siblings, 1 reply; 10+ messages in thread
From: Sandipan Das @ 2022-08-11 12:46 UTC (permalink / raw)
  To: linux-kernel, linux-perf-users, x86
  Cc: peterz, bp, acme, namhyung, jolsa, tglx, mingo, mark.rutland,
	alexander.shishkin, dave.hansen, like.xu.linux, eranian,
	ananth.narayan, ravi.bangoria, santosh.shukla, sandipan.das

Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
Record Extension Version 2 (LbrExtV2) MSRs.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 tools/arch/x86/include/asm/msr-index.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index cc615be27a54..7f9eaf497947 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -574,6 +574,9 @@
 #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
 #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
 
+/* AMD Last Branch Record MSRs */
+#define MSR_AMD64_LBR_SELECT			0xc000010e
+
 /* Fam 17h MSRs */
 #define MSR_F17H_IRPERF			0xc00000e9
 
@@ -745,6 +748,8 @@
 #define MSR_AMD_DBG_EXTN_CFG		0xc000010f
 #define MSR_AMD_SAMP_BR_FROM		0xc0010300
 
+#define DBG_EXTN_CFG_LBRV2EN		BIT_ULL(6)
+
 #define MSR_IA32_MPERF			0x000000e7
 #define MSR_IA32_APERF			0x000000e8
 
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-11 12:46 ` [PATCH 2/4] tools headers x86: Sync msr-index.h " Sandipan Das
@ 2022-08-12  8:33   ` Jiri Olsa
  2022-08-12  9:03     ` Sandipan Das
  0 siblings, 1 reply; 10+ messages in thread
From: Jiri Olsa @ 2022-08-12  8:33 UTC (permalink / raw)
  To: Sandipan Das
  Cc: linux-kernel, linux-perf-users, x86, peterz, bp, acme, namhyung,
	tglx, mingo, mark.rutland, alexander.shishkin, dave.hansen,
	like.xu.linux, eranian, ananth.narayan, ravi.bangoria,
	santosh.shukla

On Thu, Aug 11, 2022 at 06:16:47PM +0530, Sandipan Das wrote:
> Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
> Record Extension Version 2 (LbrExtV2) MSRs.
> 
> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> ---
>  tools/arch/x86/include/asm/msr-index.h | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
> index cc615be27a54..7f9eaf497947 100644
> --- a/tools/arch/x86/include/asm/msr-index.h
> +++ b/tools/arch/x86/include/asm/msr-index.h
> @@ -574,6 +574,9 @@
>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
>  
> +/* AMD Last Branch Record MSRs */
> +#define MSR_AMD64_LBR_SELECT			0xc000010e

curious do we actualy use this in tools somewhere?

jirka

> +
>  /* Fam 17h MSRs */
>  #define MSR_F17H_IRPERF			0xc00000e9
>  
> @@ -745,6 +748,8 @@
>  #define MSR_AMD_DBG_EXTN_CFG		0xc000010f
>  #define MSR_AMD_SAMP_BR_FROM		0xc0010300
>  
> +#define DBG_EXTN_CFG_LBRV2EN		BIT_ULL(6)
> +
>  #define MSR_IA32_MPERF			0x000000e7
>  #define MSR_IA32_APERF			0x000000e8
>  
> -- 
> 2.34.1
> 

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-12  8:33   ` Jiri Olsa
@ 2022-08-12  9:03     ` Sandipan Das
  2022-08-12 13:33       ` Arnaldo Carvalho de Melo
  2022-08-12 19:39       ` Arnaldo Carvalho de Melo
  0 siblings, 2 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-12  9:03 UTC (permalink / raw)
  To: Jiri Olsa
  Cc: linux-kernel, linux-perf-users, x86, peterz, bp, acme, namhyung,
	tglx, mingo, mark.rutland, alexander.shishkin, dave.hansen,
	like.xu.linux, eranian, ananth.narayan, ravi.bangoria,
	santosh.shukla

Hi Jiri,

On 8/12/2022 2:03 PM, Jiri Olsa wrote:
> On Thu, Aug 11, 2022 at 06:16:47PM +0530, Sandipan Das wrote:
>> Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
>> Record Extension Version 2 (LbrExtV2) MSRs.
>>
>> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
>> ---
>>  tools/arch/x86/include/asm/msr-index.h | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
>> index cc615be27a54..7f9eaf497947 100644
>> --- a/tools/arch/x86/include/asm/msr-index.h
>> +++ b/tools/arch/x86/include/asm/msr-index.h
>> @@ -574,6 +574,9 @@
>>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
>>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
>>  
>> +/* AMD Last Branch Record MSRs */
>> +#define MSR_AMD64_LBR_SELECT			0xc000010e
> 
> curious do we actualy use this in tools somewhere?
> 
> jirka
> 

Commit 9dde6cadb92b ("tools arch x86: Sync the msr-index.h copy with the kernel sources")
from Arnaldo says that adding these new MSR definitions in the tools headers allows the
beautification scripts to pick up new entries which can be used for filtering MSR access
traces.

E.g. one can trace the hardware LBR branch filter bits getting written to the LBR_SELECT
MSR while recording branches.

$ perf record -j any,u true
$ perf record -j any_call,u true

$ sudo perf trace -e msr:write_msr/max-stack=32/ --filter="msr == AMD64_LBR_SELECT"

[...]
224568.130 perf/9093 msr:write_msr(msr: AMD64_LBR_SELECT, val: 1)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       native_write_msr ([kernel.kallsyms])
                                       amd_pmu_lbr_enable_all ([kernel.kallsyms])
                                       amd_pmu_v2_enable_all ([kernel.kallsyms])
                                       x86_pmu_enable ([kernel.kallsyms])
                                       ctx_resched ([kernel.kallsyms])
                                       perf_event_exec ([kernel.kallsyms])
                                       begin_new_exec ([kernel.kallsyms])
                                       load_elf_binary ([kernel.kallsyms])
                                       bprm_execve ([kernel.kallsyms])
                                       do_execveat_common.isra.0 ([kernel.kallsyms])
                                       __x64_sys_execve ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
[...]
302748.439 perf/9126 msr:write_msr(msr: AMD64_LBR_SELECT, val: 229)
                                       do_trace_write_msr ([kernel.kallsyms])
                                       do_trace_write_msr ([kernel.kallsyms])
                                       native_write_msr ([kernel.kallsyms])
                                       amd_pmu_lbr_enable_all ([kernel.kallsyms])
                                       amd_pmu_v2_enable_all ([kernel.kallsyms])
                                       x86_pmu_enable ([kernel.kallsyms])
                                       ctx_resched ([kernel.kallsyms])
                                       perf_event_exec ([kernel.kallsyms])
                                       begin_new_exec ([kernel.kallsyms])
                                       load_elf_binary ([kernel.kallsyms])
                                       bprm_execve ([kernel.kallsyms])
                                       do_execveat_common.isra.0 ([kernel.kallsyms])
                                       __x64_sys_execve ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64 ([kernel.kallsyms])
                                       execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
[...]

I can add this example to the commit message in the next revision.


- Sandipan

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-12  9:03     ` Sandipan Das
@ 2022-08-12 13:33       ` Arnaldo Carvalho de Melo
  2022-08-12 19:39       ` Arnaldo Carvalho de Melo
  1 sibling, 0 replies; 10+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-08-12 13:33 UTC (permalink / raw)
  To: Sandipan Das
  Cc: Jiri Olsa, linux-kernel, linux-perf-users, x86, peterz, bp,
	namhyung, tglx, mingo, mark.rutland, alexander.shishkin,
	dave.hansen, like.xu.linux, eranian, ananth.narayan,
	ravi.bangoria, santosh.shukla

Em Fri, Aug 12, 2022 at 02:33:46PM +0530, Sandipan Das escreveu:
> Hi Jiri,
> 
> On 8/12/2022 2:03 PM, Jiri Olsa wrote:
> > On Thu, Aug 11, 2022 at 06:16:47PM +0530, Sandipan Das wrote:
> >> Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
> >> Record Extension Version 2 (LbrExtV2) MSRs.
> >>
> >> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> >> ---
> >>  tools/arch/x86/include/asm/msr-index.h | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >> diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
> >> index cc615be27a54..7f9eaf497947 100644
> >> --- a/tools/arch/x86/include/asm/msr-index.h
> >> +++ b/tools/arch/x86/include/asm/msr-index.h
> >> @@ -574,6 +574,9 @@
> >>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
> >>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
> >>  
> >> +/* AMD Last Branch Record MSRs */
> >> +#define MSR_AMD64_LBR_SELECT			0xc000010e
> > 
> > curious do we actualy use this in tools somewhere?
> > 
> > jirka
> > 
> 
> Commit 9dde6cadb92b ("tools arch x86: Sync the msr-index.h copy with the kernel sources")
> from Arnaldo says that adding these new MSR definitions in the tools headers allows the
> beautification scripts to pick up new entries which can be used for filtering MSR access
> traces.

Right, in this specific case that header should be moved to
tools/perf/trace/beauty/include/, as it is only used to harvest new MSRs
by:

⬢[acme@toolbox perf]$ tools/perf/trace/beauty/tracepoints/x86_msr.sh  | wc -l
328
⬢[acme@toolbox perf]$ tools/perf/trace/beauty/tracepoints/x86_msr.sh  | head
static const char *x86_MSRs[] = {
	[0x00000000] = "IA32_P5_MC_ADDR",
	[0x00000001] = "IA32_P5_MC_TYPE",
	[0x00000010] = "IA32_TSC",
	[0x00000017] = "IA32_PLATFORM_ID",
	[0x0000001b] = "IA32_APICBASE",
	[0x00000020] = "KNC_PERFCTR0",
	[0x00000021] = "KNC_PERFCTR1",
	[0x00000028] = "KNC_EVNTSEL0",
	[0x00000029] = "KNC_EVNTSEL1",
⬢[acme@toolbox perf]$

Other headers we have copies from the kernel may be used both for
harvesting non-enum enumerations like those to pretty print and use in
tracepoint filter expressions in 'perf trace', and in building perf on
older systems.

The preferred way is for kernel developers not to update the copies when
they add new stuff to the original file, so that perf developers have
the opportunity of checking if the new original file in the kernel don't
break the scripts in tools/perf/, or if the new additions are note
matched by regexps in the perf/tools/trace/beauty/ extraction scripts.

But kernel developers are welcome to update it iif they do these checks
themselves, at the very least do a 'make -C tools/perf' to check if it
builds before/after the update.

- Arnaldo
 
> E.g. one can trace the hardware LBR branch filter bits getting written to the LBR_SELECT
> MSR while recording branches.
> 
> $ perf record -j any,u true
> $ perf record -j any_call,u true
> 
> $ sudo perf trace -e msr:write_msr/max-stack=32/ --filter="msr == AMD64_LBR_SELECT"
> 
> [...]
> 224568.130 perf/9093 msr:write_msr(msr: AMD64_LBR_SELECT, val: 1)
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        native_write_msr ([kernel.kallsyms])
>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>                                        x86_pmu_enable ([kernel.kallsyms])
>                                        ctx_resched ([kernel.kallsyms])
>                                        perf_event_exec ([kernel.kallsyms])
>                                        begin_new_exec ([kernel.kallsyms])
>                                        load_elf_binary ([kernel.kallsyms])
>                                        bprm_execve ([kernel.kallsyms])
>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>                                        __x64_sys_execve ([kernel.kallsyms])
>                                        do_syscall_64 ([kernel.kallsyms])
>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
> [...]
> 302748.439 perf/9126 msr:write_msr(msr: AMD64_LBR_SELECT, val: 229)
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        native_write_msr ([kernel.kallsyms])
>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>                                        x86_pmu_enable ([kernel.kallsyms])
>                                        ctx_resched ([kernel.kallsyms])
>                                        perf_event_exec ([kernel.kallsyms])
>                                        begin_new_exec ([kernel.kallsyms])
>                                        load_elf_binary ([kernel.kallsyms])
>                                        bprm_execve ([kernel.kallsyms])
>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>                                        __x64_sys_execve ([kernel.kallsyms])
>                                        do_syscall_64 ([kernel.kallsyms])
>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
> [...]
> 
> I can add this example to the commit message in the next revision.
> 
> 
> - Sandipan

-- 

- Arnaldo

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-12  9:03     ` Sandipan Das
  2022-08-12 13:33       ` Arnaldo Carvalho de Melo
@ 2022-08-12 19:39       ` Arnaldo Carvalho de Melo
  2022-08-16  5:10         ` Sandipan Das
  1 sibling, 1 reply; 10+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-08-12 19:39 UTC (permalink / raw)
  To: Sandipan Das
  Cc: Jiri Olsa, linux-kernel, linux-perf-users, x86, peterz, bp,
	namhyung, tglx, mingo, mark.rutland, alexander.shishkin,
	dave.hansen, like.xu.linux, eranian, ananth.narayan,
	ravi.bangoria, santosh.shukla

Em Fri, Aug 12, 2022 at 02:33:46PM +0530, Sandipan Das escreveu:
> Hi Jiri,
> 
> On 8/12/2022 2:03 PM, Jiri Olsa wrote:
> > On Thu, Aug 11, 2022 at 06:16:47PM +0530, Sandipan Das wrote:
> >> Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
> >> Record Extension Version 2 (LbrExtV2) MSRs.
> >>
> >> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
> >> ---
> >>  tools/arch/x86/include/asm/msr-index.h | 5 +++++
> >>  1 file changed, 5 insertions(+)
> >>
> >> diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
> >> index cc615be27a54..7f9eaf497947 100644
> >> --- a/tools/arch/x86/include/asm/msr-index.h
> >> +++ b/tools/arch/x86/include/asm/msr-index.h
> >> @@ -574,6 +574,9 @@
> >>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
> >>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
> >>  
> >> +/* AMD Last Branch Record MSRs */
> >> +#define MSR_AMD64_LBR_SELECT			0xc000010e
> > 
> > curious do we actualy use this in tools somewhere?
> > 
> > jirka
> > 
> 
> Commit 9dde6cadb92b ("tools arch x86: Sync the msr-index.h copy with the kernel sources")
> from Arnaldo says that adding these new MSR definitions in the tools headers allows the
> beautification scripts to pick up new entries which can be used for filtering MSR access
> traces.
> 
> E.g. one can trace the hardware LBR branch filter bits getting written to the LBR_SELECT
> MSR while recording branches.
> 
> $ perf record -j any,u true
> $ perf record -j any_call,u true
> 
> $ sudo perf trace -e msr:write_msr/max-stack=32/ --filter="msr == AMD64_LBR_SELECT"
> 
> [...]
> 224568.130 perf/9093 msr:write_msr(msr: AMD64_LBR_SELECT, val: 1)
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        native_write_msr ([kernel.kallsyms])
>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>                                        x86_pmu_enable ([kernel.kallsyms])
>                                        ctx_resched ([kernel.kallsyms])
>                                        perf_event_exec ([kernel.kallsyms])
>                                        begin_new_exec ([kernel.kallsyms])
>                                        load_elf_binary ([kernel.kallsyms])
>                                        bprm_execve ([kernel.kallsyms])
>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>                                        __x64_sys_execve ([kernel.kallsyms])
>                                        do_syscall_64 ([kernel.kallsyms])
>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
> [...]
> 302748.439 perf/9126 msr:write_msr(msr: AMD64_LBR_SELECT, val: 229)
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        do_trace_write_msr ([kernel.kallsyms])
>                                        native_write_msr ([kernel.kallsyms])
>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>                                        x86_pmu_enable ([kernel.kallsyms])
>                                        ctx_resched ([kernel.kallsyms])
>                                        perf_event_exec ([kernel.kallsyms])
>                                        begin_new_exec ([kernel.kallsyms])
>                                        load_elf_binary ([kernel.kallsyms])
>                                        bprm_execve ([kernel.kallsyms])
>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>                                        __x64_sys_execve ([kernel.kallsyms])
>                                        do_syscall_64 ([kernel.kallsyms])
>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
> [...]
> 
> I can add this example to the commit message in the next revision.

Right, you can reuse something from my messages updating this file or,
better, show an example like you did above, for the thing that you are
working at that moment :-)

One of the things we need to do is:

perf trace -e msr:write_msr/max-stack=32/ --filter-help

And then it should look what are the strings that can be used for that
specific msr:write_msr tracepoint.

Also have tab expansion in the --filter= part :-)

- Arnaldo

^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH 2/4] tools headers x86: Sync msr-index.h with kernel sources
  2022-08-12 19:39       ` Arnaldo Carvalho de Melo
@ 2022-08-16  5:10         ` Sandipan Das
  0 siblings, 0 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-16  5:10 UTC (permalink / raw)
  To: Arnaldo Carvalho de Melo
  Cc: Jiri Olsa, linux-kernel, linux-perf-users, x86, peterz, bp,
	namhyung, tglx, mingo, mark.rutland, alexander.shishkin,
	dave.hansen, like.xu.linux, eranian, ananth.narayan,
	ravi.bangoria, santosh.shukla

Hi Arnaldo,

On 8/13/2022 1:09 AM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Aug 12, 2022 at 02:33:46PM +0530, Sandipan Das escreveu:
>> Hi Jiri,
>>
>> On 8/12/2022 2:03 PM, Jiri Olsa wrote:
>>> On Thu, Aug 11, 2022 at 06:16:47PM +0530, Sandipan Das wrote:
>>>> Sync msr-index.h with the kernel sources by adding the new AMD Last Branch
>>>> Record Extension Version 2 (LbrExtV2) MSRs.
>>>>
>>>> Signed-off-by: Sandipan Das <sandipan.das@amd.com>
>>>> ---
>>>>  tools/arch/x86/include/asm/msr-index.h | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
>>>> index cc615be27a54..7f9eaf497947 100644
>>>> --- a/tools/arch/x86/include/asm/msr-index.h
>>>> +++ b/tools/arch/x86/include/asm/msr-index.h
>>>> @@ -574,6 +574,9 @@
>>>>  #define MSR_AMD64_PERF_CNTR_GLOBAL_CTL		0xc0000301
>>>>  #define MSR_AMD64_PERF_CNTR_GLOBAL_STATUS_CLR	0xc0000302
>>>>  
>>>> +/* AMD Last Branch Record MSRs */
>>>> +#define MSR_AMD64_LBR_SELECT			0xc000010e
>>>
>>> curious do we actualy use this in tools somewhere?
>>>
>>> jirka
>>>
>>
>> Commit 9dde6cadb92b ("tools arch x86: Sync the msr-index.h copy with the kernel sources")
>> from Arnaldo says that adding these new MSR definitions in the tools headers allows the
>> beautification scripts to pick up new entries which can be used for filtering MSR access
>> traces.
>>
>> E.g. one can trace the hardware LBR branch filter bits getting written to the LBR_SELECT
>> MSR while recording branches.
>>
>> $ perf record -j any,u true
>> $ perf record -j any_call,u true
>>
>> $ sudo perf trace -e msr:write_msr/max-stack=32/ --filter="msr == AMD64_LBR_SELECT"
>>
>> [...]
>> 224568.130 perf/9093 msr:write_msr(msr: AMD64_LBR_SELECT, val: 1)
>>                                        do_trace_write_msr ([kernel.kallsyms])
>>                                        do_trace_write_msr ([kernel.kallsyms])
>>                                        native_write_msr ([kernel.kallsyms])
>>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>>                                        x86_pmu_enable ([kernel.kallsyms])
>>                                        ctx_resched ([kernel.kallsyms])
>>                                        perf_event_exec ([kernel.kallsyms])
>>                                        begin_new_exec ([kernel.kallsyms])
>>                                        load_elf_binary ([kernel.kallsyms])
>>                                        bprm_execve ([kernel.kallsyms])
>>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>>                                        __x64_sys_execve ([kernel.kallsyms])
>>                                        do_syscall_64 ([kernel.kallsyms])
>>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
>> [...]
>> 302748.439 perf/9126 msr:write_msr(msr: AMD64_LBR_SELECT, val: 229)
>>                                        do_trace_write_msr ([kernel.kallsyms])
>>                                        do_trace_write_msr ([kernel.kallsyms])
>>                                        native_write_msr ([kernel.kallsyms])
>>                                        amd_pmu_lbr_enable_all ([kernel.kallsyms])
>>                                        amd_pmu_v2_enable_all ([kernel.kallsyms])
>>                                        x86_pmu_enable ([kernel.kallsyms])
>>                                        ctx_resched ([kernel.kallsyms])
>>                                        perf_event_exec ([kernel.kallsyms])
>>                                        begin_new_exec ([kernel.kallsyms])
>>                                        load_elf_binary ([kernel.kallsyms])
>>                                        bprm_execve ([kernel.kallsyms])
>>                                        do_execveat_common.isra.0 ([kernel.kallsyms])
>>                                        __x64_sys_execve ([kernel.kallsyms])
>>                                        do_syscall_64 ([kernel.kallsyms])
>>                                        entry_SYSCALL_64 ([kernel.kallsyms])
>>                                        execve (/usr/lib/x86_64-linux-gnu/libc.so.6)
>> [...]
>>
>> I can add this example to the commit message in the next revision.
> 
> Right, you can reuse something from my messages updating this file or,
> better, show an example like you did above, for the thing that you are
> working at that moment :-)
> 
> One of the things we need to do is:
> 
> perf trace -e msr:write_msr/max-stack=32/ --filter-help
> 
> And then it should look what are the strings that can be used for that
> specific msr:write_msr tracepoint.
> 
> Also have tab expansion in the --filter= part :-)
> 

Thanks for the suggestions. Will incorporate them in the next revision.

- Sandipan

^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH 3/4] perf script: Show branch speculation info
  2022-08-11 12:46 [PATCH 0/4] tools perf: Add branch speculation info Sandipan Das
  2022-08-11 12:46 ` [PATCH 1/4] tools headers uapi: Sync perf_event.h with kernel sources Sandipan Das
  2022-08-11 12:46 ` [PATCH 2/4] tools headers x86: Sync msr-index.h " Sandipan Das
@ 2022-08-11 12:46 ` Sandipan Das
  2022-08-11 12:46 ` [PATCH 4/4] perf session: Show branch speculation info in raw dump Sandipan Das
  3 siblings, 0 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-11 12:46 UTC (permalink / raw)
  To: linux-kernel, linux-perf-users, x86
  Cc: peterz, bp, acme, namhyung, jolsa, tglx, mingo, mark.rutland,
	alexander.shishkin, dave.hansen, like.xu.linux, eranian,
	ananth.narayan, ravi.bangoria, santosh.shukla, sandipan.das

Show the branch speculation info if provided by the branch recording
hardware feature. This can be useful for optimizing code further.

The speculation info is appended to the end of the list of fields so any
existing tools that use "/" as a delimiter for access fields via an index
remain unaffected. Also show "-" instead of "N/A" when speculation info
is unavailable because "/" is used as the field separator.

E.g.

  $ perf record -j any,u,save_type ./test_branch
  $ perf script --fields brstacksym

Before:

  [...]
  check_match+0x60/strcmp+0x0/P/-/-/0/CALL
  do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL
  [...]

After:

  [...]
  check_match+0x60/strcmp+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH
  do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH
  [...]

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 tools/perf/builtin-script.c |  5 +++--
 tools/perf/util/branch.c    | 15 +++++++++++++++
 tools/perf/util/branch.h    |  5 ++++-
 tools/perf/util/evsel.c     |  9 ++++++---
 4 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index ac19fee62d8e..d294ac804244 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -872,12 +872,13 @@ mispred_str(struct branch_entry *br)
 
 static int print_bstack_flags(FILE *fp, struct branch_entry *br)
 {
-	return fprintf(fp, "/%c/%c/%c/%d/%s ",
+	return fprintf(fp, "/%c/%c/%c/%d/%s/%s ",
 		       mispred_str(br),
 		       br->flags.in_tx ? 'X' : '-',
 		       br->flags.abort ? 'A' : '-',
 		       br->flags.cycles,
-		       br->flags.type ? branch_type_name(br->flags.type) : "-");
+		       br->flags.type ? branch_type_name(br->flags.type) : "-",
+		       br->flags.spec ? branch_spec_desc(br->flags.spec) : "-");
 }
 
 static int perf_sample__fprintf_brstack(struct perf_sample *sample,
diff --git a/tools/perf/util/branch.c b/tools/perf/util/branch.c
index a9a909db8cc7..29d89425a011 100644
--- a/tools/perf/util/branch.c
+++ b/tools/perf/util/branch.c
@@ -146,3 +146,18 @@ int branch_type_str(struct branch_type_stat *st, char *bf, int size)
 
 	return printed;
 }
+
+const char *branch_spec_desc(int spec)
+{
+	const char *branch_spec_outcomes[PERF_BR_SPEC_MAX] = {
+		"N/A",
+		"SPEC_WRONG_PATH",
+		"NON_SPEC_CORRECT_PATH",
+		"SPEC_CORRECT_PATH",
+	};
+
+	if (spec >= 0 && spec < PERF_BR_SPEC_MAX)
+		return branch_spec_outcomes[spec];
+
+	return NULL;
+}
diff --git a/tools/perf/util/branch.h b/tools/perf/util/branch.h
index 17b2ccc61094..8563b88b8281 100644
--- a/tools/perf/util/branch.h
+++ b/tools/perf/util/branch.h
@@ -24,7 +24,8 @@ struct branch_flags {
 			u64 abort:1;
 			u64 cycles:16;
 			u64 type:4;
-			u64 reserved:40;
+			u64 spec:2;
+			u64 reserved:38;
 		};
 	};
 };
@@ -85,4 +86,6 @@ const char *branch_type_name(int type);
 void branch_type_stat_display(FILE *fp, struct branch_type_stat *st);
 int branch_type_str(struct branch_type_stat *st, char *bf, int bfsize);
 
+const char *branch_spec_desc(int spec);
+
 #endif /* _PERF_BRANCH_H */
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 4852089e1d79..e47cf16bef0a 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2313,7 +2313,8 @@ u64 evsel__bitfield_swap_branch_flags(u64 value)
 	 * 		abort:1		//transaction abort
 	 * 		cycles:16	//cycle count to last branch
 	 * 		type:4		//branch type
-	 * 		reserved:40
+	 * 		spec:2		//branch speculation info
+	 * 		reserved:38
 	 * 	}
 	 * }
 	 *
@@ -2332,7 +2333,8 @@ u64 evsel__bitfield_swap_branch_flags(u64 value)
 		new_val |= bitfield_swap(value, 3, 1);
 		new_val |= bitfield_swap(value, 4, 16);
 		new_val |= bitfield_swap(value, 20, 4);
-		new_val |= bitfield_swap(value, 24, 40);
+		new_val |= bitfield_swap(value, 24, 2);
+		new_val |= bitfield_swap(value, 26, 38);
 	} else {
 		new_val = bitfield_swap(value, 63, 1);
 		new_val |= bitfield_swap(value, 62, 1);
@@ -2340,7 +2342,8 @@ u64 evsel__bitfield_swap_branch_flags(u64 value)
 		new_val |= bitfield_swap(value, 60, 1);
 		new_val |= bitfield_swap(value, 44, 16);
 		new_val |= bitfield_swap(value, 40, 4);
-		new_val |= bitfield_swap(value, 0, 40);
+		new_val |= bitfield_swap(value, 38, 2);
+		new_val |= bitfield_swap(value, 0, 38);
 	}
 
 	return new_val;
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH 4/4] perf session: Show branch speculation info in raw dump
  2022-08-11 12:46 [PATCH 0/4] tools perf: Add branch speculation info Sandipan Das
                   ` (2 preceding siblings ...)
  2022-08-11 12:46 ` [PATCH 3/4] perf script: Show branch speculation info Sandipan Das
@ 2022-08-11 12:46 ` Sandipan Das
  3 siblings, 0 replies; 10+ messages in thread
From: Sandipan Das @ 2022-08-11 12:46 UTC (permalink / raw)
  To: linux-kernel, linux-perf-users, x86
  Cc: peterz, bp, acme, namhyung, jolsa, tglx, mingo, mark.rutland,
	alexander.shishkin, dave.hansen, like.xu.linux, eranian,
	ananth.narayan, ravi.bangoria, santosh.shukla, sandipan.das

Show the branch speculation info if provided by the branch recording
hardware feature. This can be useful for optimizing code further.

E.g.

  $ perf record -j any,u ./test_branch
  $ perf report --dump-raw-trace

Before:

  [...]
  8380958377610 0x40b178 [0x1b0]: PERF_RECORD_SAMPLE(IP, 0x2): 7952/7952: 0x4f851a period: 48973 addr: 0
  ... branch stack: nr:16
  .....  0: 00000000004b52fd -> 00000000004f82c0 0 cycles  P   0
  .....  1: ffffffff8220137c -> 00000000004b52f0 0 cycles M    0
  .....  2: 000000000041d1c4 -> 00000000004b52f0 0 cycles  P   0
  .....  3: 00000000004e7ead -> 000000000041d1b0 0 cycles M    0
  .....  4: 00000000004e7f91 -> 00000000004e7ead 0 cycles  P   0
  .....  5: 00000000004e7ea8 -> 00000000004e7f70 0 cycles  P   0
  .....  6: 00000000004e7e52 -> 00000000004e7e98 0 cycles M    0
  .....  7: 00000000004e7e1f -> 00000000004e7e40 0 cycles M    0
  .....  8: 00000000004e7f60 -> 00000000004e7df0 0 cycles  P   0
  .....  9: 00000000004e7f58 -> 00000000004e7f60 0 cycles M    0
  ..... 10: 000000000041d85d -> 00000000004e7f50 0 cycles  P   0
  ..... 11: 000000000043306a -> 000000000041d840 0 cycles  P   0
  ..... 12: ffffffff8220137c -> 0000000000433040 0 cycles M    0
  ..... 13: 000000000041e4a1 -> 0000000000433040 0 cycles  P   0
  ..... 14: ffffffff8220137c -> 000000000041e490 0 cycles M    0
  ..... 15: 000000000041d89b -> 000000000041e487 0 cycles  P   0
   ... thread: test_branch:7952
   ...... dso: /data/sandipan/test_branch
  [...]

After:

  [...]
  8380958377610 0x40b178 [0x1b0]: PERF_RECORD_SAMPLE(IP, 0x2): 7952/7952: 0x4f851a period: 48973 addr: 0
  ... branch stack: nr:16
  .....  0: 00000000004b52fd -> 00000000004f82c0 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  .....  1: ffffffff8220137c -> 00000000004b52f0 0 cycles M    0  NON_SPEC_CORRECT_PATH
  .....  2: 000000000041d1c4 -> 00000000004b52f0 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  .....  3: 00000000004e7ead -> 000000000041d1b0 0 cycles M    0  NON_SPEC_CORRECT_PATH
  .....  4: 00000000004e7f91 -> 00000000004e7ead 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  .....  5: 00000000004e7ea8 -> 00000000004e7f70 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  .....  6: 00000000004e7e52 -> 00000000004e7e98 0 cycles M    0  SPEC_CORRECT_PATH
  .....  7: 00000000004e7e1f -> 00000000004e7e40 0 cycles M    0  NON_SPEC_CORRECT_PATH
  .....  8: 00000000004e7f60 -> 00000000004e7df0 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  .....  9: 00000000004e7f58 -> 00000000004e7f60 0 cycles M    0  NON_SPEC_CORRECT_PATH
  ..... 10: 000000000041d85d -> 00000000004e7f50 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  ..... 11: 000000000043306a -> 000000000041d840 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  ..... 12: ffffffff8220137c -> 0000000000433040 0 cycles M    0  NON_SPEC_CORRECT_PATH
  ..... 13: 000000000041e4a1 -> 0000000000433040 0 cycles  P   0  NON_SPEC_CORRECT_PATH
  ..... 14: ffffffff8220137c -> 000000000041e490 0 cycles M    0  NON_SPEC_CORRECT_PATH
  ..... 15: 000000000041d89b -> 000000000041e487 0 cycles  P   0  NON_SPEC_CORRECT_PATH
   ... thread: test_branch:7952
   ...... dso: /data/sandipan/test_branch
  [...]

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 tools/perf/util/session.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 98e16659a149..39ba4a21aa42 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1172,7 +1172,7 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
 		struct branch_entry *e = &entries[i];
 
 		if (!callstack) {
-			printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 " %hu cycles %s%s%s%s %x %s\n",
+			printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 " %hu cycles %s%s%s%s %x %s %s\n",
 				i, e->from, e->to,
 				(unsigned short)e->flags.cycles,
 				e->flags.mispred ? "M" : " ",
@@ -1180,7 +1180,8 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
 				e->flags.abort ? "A" : " ",
 				e->flags.in_tx ? "T" : " ",
 				(unsigned)e->flags.reserved,
-				e->flags.type ? branch_type_name(e->flags.type) : "");
+				e->flags.type ? branch_type_name(e->flags.type) : "",
+				e->flags.spec ? branch_spec_desc(e->flags.spec) : "");
 		} else {
 			if (i == 0) {
 				printf("..... %2"PRIu64": %016" PRIx64 "\n"
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2022-08-16  7:56 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-08-11 12:46 [PATCH 0/4] tools perf: Add branch speculation info Sandipan Das
2022-08-11 12:46 ` [PATCH 1/4] tools headers uapi: Sync perf_event.h with kernel sources Sandipan Das
2022-08-11 12:46 ` [PATCH 2/4] tools headers x86: Sync msr-index.h " Sandipan Das
2022-08-12  8:33   ` Jiri Olsa
2022-08-12  9:03     ` Sandipan Das
2022-08-12 13:33       ` Arnaldo Carvalho de Melo
2022-08-12 19:39       ` Arnaldo Carvalho de Melo
2022-08-16  5:10         ` Sandipan Das
2022-08-11 12:46 ` [PATCH 3/4] perf script: Show branch speculation info Sandipan Das
2022-08-11 12:46 ` [PATCH 4/4] perf session: Show branch speculation info in raw dump Sandipan Das

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