* [PATCH 0/2] Ftrace fixes
@ 2017-11-01 14:33 Julien Thierry
2017-11-01 14:33 ` [PATCH 1/2] arm64: Fix static use of function graph Julien Thierry
2017-11-01 14:33 ` Julien Thierry
0 siblings, 2 replies; 13+ messages in thread
From: Julien Thierry @ 2017-11-01 14:33 UTC (permalink / raw)
To: linux-arm-kernel
Hi,
>From what Steve Rostedt said, we shouldn't rely on ftrace_trace_function
not being ftrace_stub when using the function graph tracer. As x86 does,
always check whether function graph tracing is requested in static tracing.
While testing that I didn't break things, I discovered that the perf ftrace
builtin doesn't handle kernels built without function graph tracer
(regardless of whether tracing is dynamic or not).
First patch fixes the ftrace issue.
Second patch fixes the perf front-end.
Cheers,
Julien Thierry (2):
arm64: Fix static use of function graph
perf: Fix ftrace builtin when kernel doesn't have function_graph
arch/arm64/kernel/entry-ftrace.S | 12 +++---------
tools/perf/builtin-ftrace.c | 3 ++-
2 files changed, 5 insertions(+), 10 deletions(-)
--
1.9.1
^ permalink raw reply [flat|nested] 13+ messages in thread* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-01 14:33 [PATCH 0/2] Ftrace fixes Julien Thierry @ 2017-11-01 14:33 ` Julien Thierry 2017-11-01 16:43 ` Steven Rostedt 2017-11-02 4:43 ` AKASHI Takahiro 2017-11-01 14:33 ` Julien Thierry 1 sibling, 2 replies; 13+ messages in thread From: Julien Thierry @ 2017-11-01 14:33 UTC (permalink / raw) To: linux-arm-kernel Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not set. This is because ftrace_function_trace is not always set to ftrace_stub when function_graph is in use. Do not skip checking of graph tracer functions when ftrace_function_trace is set. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/kernel/entry-ftrace.S | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index e1be42e..1175f58 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -108,13 +108,8 @@ ENTRY(_mcount) mcount_get_lr x1 // function's lr (= parent's pc) blr x2 // (*ftrace_trace_function)(pc, lr); -#ifndef CONFIG_FUNCTION_GRAPH_TRACER -skip_ftrace_call: // return; - mcount_exit // } -#else - mcount_exit // return; - // } -skip_ftrace_call: +skip_ftrace_call: // } +#ifdef CONFIG_FUNCTION_GRAPH_TRACER ldr_l x2, ftrace_graph_return cmp x0, x2 // if ((ftrace_graph_return b.ne ftrace_graph_caller // != ftrace_stub) @@ -123,9 +118,8 @@ skip_ftrace_call: adr_l x0, ftrace_graph_entry_stub // != ftrace_graph_entry_stub)) cmp x0, x2 b.ne ftrace_graph_caller // ftrace_graph_caller(); - - mcount_exit #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + mcount_exit ENDPROC(_mcount) #else /* CONFIG_DYNAMIC_FTRACE */ -- 1.9.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-01 14:33 ` [PATCH 1/2] arm64: Fix static use of function graph Julien Thierry @ 2017-11-01 16:43 ` Steven Rostedt 2017-11-02 4:43 ` AKASHI Takahiro 1 sibling, 0 replies; 13+ messages in thread From: Steven Rostedt @ 2017-11-01 16:43 UTC (permalink / raw) To: linux-arm-kernel On Wed, 1 Nov 2017 14:33:43 +0000 Julien Thierry <julien.thierry@arm.com> wrote: > Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not > set. This is because ftrace_function_trace is not always set to ftrace_stub > when function_graph is in use. > > Do not skip checking of graph tracer functions when ftrace_function_trace > is set. > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> My arm code is very rusty and I have no idea if this works or not, but for what it's worth. Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> -- Steve > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> > --- > arch/arm64/kernel/entry-ftrace.S | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S > index e1be42e..1175f58 100644 > --- a/arch/arm64/kernel/entry-ftrace.S > +++ b/arch/arm64/kernel/entry-ftrace.S > @@ -108,13 +108,8 @@ ENTRY(_mcount) > mcount_get_lr x1 // function's lr (= parent's pc) > blr x2 // (*ftrace_trace_function)(pc, lr); > > -#ifndef CONFIG_FUNCTION_GRAPH_TRACER > -skip_ftrace_call: // return; > - mcount_exit // } > -#else > - mcount_exit // return; > - // } > -skip_ftrace_call: > +skip_ftrace_call: // } > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER > ldr_l x2, ftrace_graph_return > cmp x0, x2 // if ((ftrace_graph_return > b.ne ftrace_graph_caller // != ftrace_stub) > @@ -123,9 +118,8 @@ skip_ftrace_call: > adr_l x0, ftrace_graph_entry_stub // != ftrace_graph_entry_stub)) > cmp x0, x2 > b.ne ftrace_graph_caller // ftrace_graph_caller(); > - > - mcount_exit > #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ > + mcount_exit > ENDPROC(_mcount) > > #else /* CONFIG_DYNAMIC_FTRACE */ > -- > 1.9.1 ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-01 14:33 ` [PATCH 1/2] arm64: Fix static use of function graph Julien Thierry 2017-11-01 16:43 ` Steven Rostedt @ 2017-11-02 4:43 ` AKASHI Takahiro 2017-11-02 10:18 ` Russell King - ARM Linux 1 sibling, 1 reply; 13+ messages in thread From: AKASHI Takahiro @ 2017-11-02 4:43 UTC (permalink / raw) To: linux-arm-kernel On Wed, Nov 01, 2017 at 02:33:43PM +0000, Julien Thierry wrote: > Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not > set. This is because ftrace_function_trace is not always set to ftrace_stub > when function_graph is in use. > > Do not skip checking of graph tracer functions when ftrace_function_trace > is set. > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Reviewed-by: AKASHI Takahiro <takahiro.akashi@linaro.org> I think that arm has the same issue, hoping the following patch will fix it: === >From e25bcf50d1acde698285a0c64f72d97f8b17e3fb Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro <takahiro.akashi@linaro.org> Date: Thu, 2 Nov 2017 11:35:04 +0900 Subject: [PATCH] arm: ftrace: function_graph with DYNAMIC_FTRACE --- arch/arm/kernel/entry-ftrace.S | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S index efcd9f25a14b..ef94c73ad996 100644 --- a/arch/arm/kernel/entry-ftrace.S +++ b/arch/arm/kernel/entry-ftrace.S @@ -68,8 +68,12 @@ ldr r2, [r0] adr r0, .Lftrace_stub cmp r0, r2 - bne 1f + beq 1f + mcount_get_lr r1 @ lr of instrumented func + mcount_adjust_addr r0, lr @ instrumented function + blx r2 +1: #ifdef CONFIG_FUNCTION_GRAPH_TRACER ldr r1, =ftrace_graph_return ldr r2, [r1] @@ -84,12 +88,6 @@ #endif mcount_exit - -1: mcount_get_lr r1 @ lr of instrumented func - mcount_adjust_addr r0, lr @ instrumented function - badr lr, 2f - mov pc, r2 -2: mcount_exit .endm #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS -- 2.14.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-02 4:43 ` AKASHI Takahiro @ 2017-11-02 10:18 ` Russell King - ARM Linux 2017-11-03 9:25 ` Julien Thierry 0 siblings, 1 reply; 13+ messages in thread From: Russell King - ARM Linux @ 2017-11-02 10:18 UTC (permalink / raw) To: linux-arm-kernel On Thu, Nov 02, 2017 at 01:43:07PM +0900, AKASHI Takahiro wrote: > On Wed, Nov 01, 2017 at 02:33:43PM +0000, Julien Thierry wrote: > > Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not > > set. This is because ftrace_function_trace is not always set to ftrace_stub > > when function_graph is in use. > > > > Do not skip checking of graph tracer functions when ftrace_function_trace > > is set. > > > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > Cc: Mark Rutland <mark.rutland@arm.com> > > Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> > > Reviewed-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > > I think that arm has the same issue, hoping the following patch > will fix it: > === > >From e25bcf50d1acde698285a0c64f72d97f8b17e3fb Mon Sep 17 00:00:00 2001 > From: AKASHI Takahiro <takahiro.akashi@linaro.org> > Date: Thu, 2 Nov 2017 11:35:04 +0900 > Subject: [PATCH] arm: ftrace: function_graph with DYNAMIC_FTRACE > > --- > arch/arm/kernel/entry-ftrace.S | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S > index efcd9f25a14b..ef94c73ad996 100644 > --- a/arch/arm/kernel/entry-ftrace.S > +++ b/arch/arm/kernel/entry-ftrace.S > @@ -68,8 +68,12 @@ > ldr r2, [r0] > adr r0, .Lftrace_stub > cmp r0, r2 > - bne 1f > + beq 1f > > + mcount_get_lr r1 @ lr of instrumented func > + mcount_adjust_addr r0, lr @ instrumented function > + blx r2 NAK. Not all CPUs support "blx". I don't see why you'd make this gratuitous change when just moving code around. Please separate your changes in future. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-02 10:18 ` Russell King - ARM Linux @ 2017-11-03 9:25 ` Julien Thierry 2017-11-06 1:36 ` AKASHI Takahiro 0 siblings, 1 reply; 13+ messages in thread From: Julien Thierry @ 2017-11-03 9:25 UTC (permalink / raw) To: linux-arm-kernel Hi, On 02/11/17 10:18, Russell King - ARM Linux wrote: > On Thu, Nov 02, 2017 at 01:43:07PM +0900, AKASHI Takahiro wrote: >> On Wed, Nov 01, 2017 at 02:33:43PM +0000, Julien Thierry wrote: >>> Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not >>> set. This is because ftrace_function_trace is not always set to ftrace_stub >>> when function_graph is in use. >>> >>> Do not skip checking of graph tracer functions when ftrace_function_trace >>> is set. >>> >>> Signed-off-by: Julien Thierry <julien.thierry@arm.com> >>> Cc: Catalin Marinas <catalin.marinas@arm.com> >>> Cc: Will Deacon <will.deacon@arm.com> >>> Cc: Mark Rutland <mark.rutland@arm.com> >>> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> >> >> Reviewed-by: AKASHI Takahiro <takahiro.akashi@linaro.org> >> >> I think that arm has the same issue, hoping the following patch >> will fix it: Thanks for noticing this and for the patch. I'll re-spin a version for this series and include your patch. >> === >> >From e25bcf50d1acde698285a0c64f72d97f8b17e3fb Mon Sep 17 00:00:00 2001 >> From: AKASHI Takahiro <takahiro.akashi@linaro.org> >> Date: Thu, 2 Nov 2017 11:35:04 +0900 >> Subject: [PATCH] arm: ftrace: function_graph with DYNAMIC_FTRACE >> >> --- >> arch/arm/kernel/entry-ftrace.S | 12 +++++------- >> 1 file changed, 5 insertions(+), 7 deletions(-) >> >> diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S >> index efcd9f25a14b..ef94c73ad996 100644 >> --- a/arch/arm/kernel/entry-ftrace.S >> +++ b/arch/arm/kernel/entry-ftrace.S >> @@ -68,8 +68,12 @@ >> ldr r2, [r0] >> adr r0, .Lftrace_stub >> cmp r0, r2 >> - bne 1f >> + beq 1f >> >> + mcount_get_lr r1 @ lr of instrumented func >> + mcount_adjust_addr r0, lr @ instrumented function >> + blx r2 > > NAK. Not all CPUs support "blx". I don't see why you'd make this > gratuitous change when just moving code around. Please separate > your changes in future. > I'll change the blx back to the badr + mov instructions in the new version. Thanks, -- Julien Thierry ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 1/2] arm64: Fix static use of function graph 2017-11-03 9:25 ` Julien Thierry @ 2017-11-06 1:36 ` AKASHI Takahiro 0 siblings, 0 replies; 13+ messages in thread From: AKASHI Takahiro @ 2017-11-06 1:36 UTC (permalink / raw) To: linux-arm-kernel On Fri, Nov 03, 2017 at 09:25:07AM +0000, Julien Thierry wrote: > Hi, > > On 02/11/17 10:18, Russell King - ARM Linux wrote: > >On Thu, Nov 02, 2017 at 01:43:07PM +0900, AKASHI Takahiro wrote: > >>On Wed, Nov 01, 2017 at 02:33:43PM +0000, Julien Thierry wrote: > >>>Function graph does not work currently when CONFIG_DYNAMIC_TRACE is not > >>>set. This is because ftrace_function_trace is not always set to ftrace_stub > >>>when function_graph is in use. > >>> > >>>Do not skip checking of graph tracer functions when ftrace_function_trace > >>>is set. > >>> > >>>Signed-off-by: Julien Thierry <julien.thierry@arm.com> > >>>Cc: Catalin Marinas <catalin.marinas@arm.com> > >>>Cc: Will Deacon <will.deacon@arm.com> > >>>Cc: Mark Rutland <mark.rutland@arm.com> > >>>Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> > >> > >>Reviewed-by: AKASHI Takahiro <takahiro.akashi@linaro.org> > >> > >>I think that arm has the same issue, hoping the following patch > >>will fix it: > > Thanks for noticing this and for the patch. I'll re-spin a version for this > series and include your patch. Thanks. You'd better fix a bug in the subject, which should be "!DYNAMIC_FTRACE" or use the same title as yours. -Takahiro AKASHI > >>=== > >>>From e25bcf50d1acde698285a0c64f72d97f8b17e3fb Mon Sep 17 00:00:00 2001 > >>From: AKASHI Takahiro <takahiro.akashi@linaro.org> > >>Date: Thu, 2 Nov 2017 11:35:04 +0900 > >>Subject: [PATCH] arm: ftrace: function_graph with DYNAMIC_FTRACE > >> > >>--- > >> arch/arm/kernel/entry-ftrace.S | 12 +++++------- > >> 1 file changed, 5 insertions(+), 7 deletions(-) > >> > >>diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S > >>index efcd9f25a14b..ef94c73ad996 100644 > >>--- a/arch/arm/kernel/entry-ftrace.S > >>+++ b/arch/arm/kernel/entry-ftrace.S > >>@@ -68,8 +68,12 @@ > >> ldr r2, [r0] > >> adr r0, .Lftrace_stub > >> cmp r0, r2 > >>- bne 1f > >>+ beq 1f > >>+ mcount_get_lr r1 @ lr of instrumented func > >>+ mcount_adjust_addr r0, lr @ instrumented function > >>+ blx r2 > > > >NAK. Not all CPUs support "blx". I don't see why you'd make this > >gratuitous change when just moving code around. Please separate > >your changes in future. > > > > I'll change the blx back to the badr + mov instructions in the new version. > > Thanks, > > -- > Julien Thierry ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph 2017-11-01 14:33 [PATCH 0/2] Ftrace fixes Julien Thierry @ 2017-11-01 14:33 ` Julien Thierry 2017-11-01 14:33 ` Julien Thierry 1 sibling, 0 replies; 13+ messages in thread From: Julien Thierry @ 2017-11-01 14:33 UTC (permalink / raw) To: linux-arm-kernel Cc: takahiro.akashi, rostedt, Julien Thierry, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, linux-kernel When linux is built without support for function graph tracer, the ftrace builtin of perf will fail when trying to reset max_graph_depth because the file does not exist. This prevents the use of function tracer from perf. Do not attempt to write this file when the tracer in use is not function_graph. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-kernel@vger.kernel.org --- tools/perf/builtin-ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 25a42ac..48120f2 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) if (reset_tracing_cpu() < 0) return -1; - if (write_tracing_file("max_graph_depth", "0") < 0) + if (!strcmp(ftrace->tracer, "function_graph") && + write_tracing_file("max_graph_depth", "0") < 0) return -1; reset_tracing_filters(); -- 1.9.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph @ 2017-11-01 14:33 ` Julien Thierry 0 siblings, 0 replies; 13+ messages in thread From: Julien Thierry @ 2017-11-01 14:33 UTC (permalink / raw) To: linux-arm-kernel When linux is built without support for function graph tracer, the ftrace builtin of perf will fail when trying to reset max_graph_depth because the file does not exist. This prevents the use of function tracer from perf. Do not attempt to write this file when the tracer in use is not function_graph. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-kernel at vger.kernel.org --- tools/perf/builtin-ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c index 25a42ac..48120f2 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) if (reset_tracing_cpu() < 0) return -1; - if (write_tracing_file("max_graph_depth", "0") < 0) + if (!strcmp(ftrace->tracer, "function_graph") && + write_tracing_file("max_graph_depth", "0") < 0) return -1; reset_tracing_filters(); -- 1.9.1 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph 2017-11-01 14:33 ` Julien Thierry @ 2017-11-01 16:44 ` Steven Rostedt -1 siblings, 0 replies; 13+ messages in thread From: Steven Rostedt @ 2017-11-01 16:44 UTC (permalink / raw) To: Julien Thierry Cc: linux-arm-kernel, takahiro.akashi, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, linux-kernel On Wed, 1 Nov 2017 14:33:44 +0000 Julien Thierry <julien.thierry@arm.com> wrote: > When linux is built without support for function graph tracer, the ftrace > builtin of perf will fail when trying to reset max_graph_depth because the > file does not exist. This prevents the use of function tracer from perf. > > Do not attempt to write this file when the tracer in use is not > function_graph. > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: linux-kernel@vger.kernel.org > --- > tools/perf/builtin-ftrace.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c > index 25a42ac..48120f2 100644 > --- a/tools/perf/builtin-ftrace.c > +++ b/tools/perf/builtin-ftrace.c > @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) > if (reset_tracing_cpu() < 0) > return -1; > > - if (write_tracing_file("max_graph_depth", "0") < 0) > + if (!strcmp(ftrace->tracer, "function_graph") && > + write_tracing_file("max_graph_depth", "0") < 0) Hmm, instead of doing this, could we just do a stat on the file first. As with trace-cmd, I like to reset files like this even when not enabling function_graph tracer. -- Steve > return -1; > > reset_tracing_filters(); > -- > 1.9.1 ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph @ 2017-11-01 16:44 ` Steven Rostedt 0 siblings, 0 replies; 13+ messages in thread From: Steven Rostedt @ 2017-11-01 16:44 UTC (permalink / raw) To: linux-arm-kernel On Wed, 1 Nov 2017 14:33:44 +0000 Julien Thierry <julien.thierry@arm.com> wrote: > When linux is built without support for function graph tracer, the ftrace > builtin of perf will fail when trying to reset max_graph_depth because the > file does not exist. This prevents the use of function tracer from perf. > > Do not attempt to write this file when the tracer in use is not > function_graph. > > Signed-off-by: Julien Thierry <julien.thierry@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: linux-kernel at vger.kernel.org > --- > tools/perf/builtin-ftrace.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c > index 25a42ac..48120f2 100644 > --- a/tools/perf/builtin-ftrace.c > +++ b/tools/perf/builtin-ftrace.c > @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) > if (reset_tracing_cpu() < 0) > return -1; > > - if (write_tracing_file("max_graph_depth", "0") < 0) > + if (!strcmp(ftrace->tracer, "function_graph") && > + write_tracing_file("max_graph_depth", "0") < 0) Hmm, instead of doing this, could we just do a stat on the file first. As with trace-cmd, I like to reset files like this even when not enabling function_graph tracer. -- Steve > return -1; > > reset_tracing_filters(); > -- > 1.9.1 ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph 2017-11-01 16:44 ` Steven Rostedt @ 2017-11-01 16:58 ` Julien Thierry -1 siblings, 0 replies; 13+ messages in thread From: Julien Thierry @ 2017-11-01 16:58 UTC (permalink / raw) To: Steven Rostedt Cc: linux-arm-kernel, takahiro.akashi, Will Deacon, Mark Rutland, Peter Zijlstra, Ingo Molnar, linux-kernel On 01/11/17 16:44, Steven Rostedt wrote: > On Wed, 1 Nov 2017 14:33:44 +0000 > Julien Thierry <julien.thierry@arm.com> wrote: > >> When linux is built without support for function graph tracer, the ftrace >> builtin of perf will fail when trying to reset max_graph_depth because the >> file does not exist. This prevents the use of function tracer from perf. >> >> Do not attempt to write this file when the tracer in use is not >> function_graph. >> >> Signed-off-by: Julien Thierry <julien.thierry@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: linux-kernel@vger.kernel.org >> --- >> tools/perf/builtin-ftrace.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c >> index 25a42ac..48120f2 100644 >> --- a/tools/perf/builtin-ftrace.c >> +++ b/tools/perf/builtin-ftrace.c >> @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) >> if (reset_tracing_cpu() < 0) >> return -1; >> >> - if (write_tracing_file("max_graph_depth", "0") < 0) >> + if (!strcmp(ftrace->tracer, "function_graph") && >> + write_tracing_file("max_graph_depth", "0") < 0) > > Hmm, instead of doing this, could we just do a stat on the file first. > As with trace-cmd, I like to reset files like this even when not > enabling function_graph tracer. > Sounds reasonable. I'll include that change in the next version of the patches. Thanks, -- Julien Thierry ^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph @ 2017-11-01 16:58 ` Julien Thierry 0 siblings, 0 replies; 13+ messages in thread From: Julien Thierry @ 2017-11-01 16:58 UTC (permalink / raw) To: linux-arm-kernel On 01/11/17 16:44, Steven Rostedt wrote: > On Wed, 1 Nov 2017 14:33:44 +0000 > Julien Thierry <julien.thierry@arm.com> wrote: > >> When linux is built without support for function graph tracer, the ftrace >> builtin of perf will fail when trying to reset max_graph_depth because the >> file does not exist. This prevents the use of function tracer from perf. >> >> Do not attempt to write this file when the tracer in use is not >> function_graph. >> >> Signed-off-by: Julien Thierry <julien.thierry@arm.com> >> Cc: Will Deacon <will.deacon@arm.com> >> Cc: Mark Rutland <mark.rutland@arm.com> >> Cc: Peter Zijlstra <peterz@infradead.org> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: linux-kernel at vger.kernel.org >> --- >> tools/perf/builtin-ftrace.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c >> index 25a42ac..48120f2 100644 >> --- a/tools/perf/builtin-ftrace.c >> +++ b/tools/perf/builtin-ftrace.c >> @@ -130,7 +130,8 @@ static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused) >> if (reset_tracing_cpu() < 0) >> return -1; >> >> - if (write_tracing_file("max_graph_depth", "0") < 0) >> + if (!strcmp(ftrace->tracer, "function_graph") && >> + write_tracing_file("max_graph_depth", "0") < 0) > > Hmm, instead of doing this, could we just do a stat on the file first. > As with trace-cmd, I like to reset files like this even when not > enabling function_graph tracer. > Sounds reasonable. I'll include that change in the next version of the patches. Thanks, -- Julien Thierry ^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2017-11-06 1:36 UTC | newest] Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-11-01 14:33 [PATCH 0/2] Ftrace fixes Julien Thierry 2017-11-01 14:33 ` [PATCH 1/2] arm64: Fix static use of function graph Julien Thierry 2017-11-01 16:43 ` Steven Rostedt 2017-11-02 4:43 ` AKASHI Takahiro 2017-11-02 10:18 ` Russell King - ARM Linux 2017-11-03 9:25 ` Julien Thierry 2017-11-06 1:36 ` AKASHI Takahiro 2017-11-01 14:33 ` [PATCH 2/2] perf: Fix ftrace builtin when kernel doesn't have function_graph Julien Thierry 2017-11-01 14:33 ` Julien Thierry 2017-11-01 16:44 ` Steven Rostedt 2017-11-01 16:44 ` Steven Rostedt 2017-11-01 16:58 ` Julien Thierry 2017-11-01 16:58 ` Julien Thierry
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