Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Naveen N. Rao]

On 2015/09/24 10:15PM, Naveen N Rao wrote:
> On 2015/09/24 08:32AM, Stephane Eranian wrote:
> > On Thu, Sep 24, 2015 at 5:57 AM, Jiri Olsa <jolsa@redhat.com> wrote:
> > >
> > > On Thu, Sep 24, 2015 at 05:41:58PM +0530, Naveen N. Rao wrote:
> > > > perf build currently fails on powerpc:
> > > >
> > > >   LINK     perf
> > > > libperf.a(libperf-in.o):(.toc+0x120): undefined reference to
> > > > `sample_reg_masks'
> > > > libperf.a(libperf-in.o):(.toc+0x130): undefined reference to
> > > > `sample_reg_masks'
> > > > collect2: error: ld returned 1 exit status
> > > > make[1]: *** [perf] Error 1
> > > > make: *** [all] Error 2
> > > >
> > > > This is due to parse-regs-options.c using sample_reg_masks, which is
> > > > defined only with CONFIG_PERF_REGS.
> > > >
> > > > In addition, perf record -I is only useful if the arch supports
> > > > PERF_REGS. Hence, let's expose -I conditionally.
> > > >
> > > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> > >
> > > hum, I wonder why we have sample_reg_masks defined as weak in util/perf_regs.c
> > > which is also built only via CONFIG_PERF_REGS
> > >
> > > I wonder we could get rid of the weak definition via attached patch, Stephane?
> > >
> > But the whole point of having it weak is to avoid this error scenario
> > on any arch without support
> > and avoid ugly #ifdef HAVE_ in generic files.
> > 
> > if perf_regs.c is compiled on PPC, then why do we get the undefined?
> 
> As Jiri Olsa pointed out, powerpc and many other architectures don't 
> (yet) have support for perf regs.
> 
> But, the larger reason to introduce #ifdef is so the user doesn't see 
> options (s)he can't use on a specific architecture, along the same lines 
> as builtin-probe.c

Stephane, Arnaldo,
Suka has also posted a fix for this with a different approach [1]. Can 
you please ack/pull one of these versions? Building perf is broken on 
v4.3-rc due to this.

[1] http://article.gmane.org/gmane.linux.kernel/2046370

Thanks,
Naveen

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Jiri Olsa]

On Tue, Sep 29, 2015 at 11:06:17AM +0530, Naveen N. Rao wrote:
> On 2015/09/24 10:15PM, Naveen N Rao wrote:
> > On 2015/09/24 08:32AM, Stephane Eranian wrote:
> > > On Thu, Sep 24, 2015 at 5:57 AM, Jiri Olsa <jolsa@redhat.com> wrote:
> > > >
> > > > On Thu, Sep 24, 2015 at 05:41:58PM +0530, Naveen N. Rao wrote:
> > > > > perf build currently fails on powerpc:
> > > > >
> > > > >   LINK     perf
> > > > > libperf.a(libperf-in.o):(.toc+0x120): undefined reference to
> > > > > `sample_reg_masks'
> > > > > libperf.a(libperf-in.o):(.toc+0x130): undefined reference to
> > > > > `sample_reg_masks'
> > > > > collect2: error: ld returned 1 exit status
> > > > > make[1]: *** [perf] Error 1
> > > > > make: *** [all] Error 2
> > > > >
> > > > > This is due to parse-regs-options.c using sample_reg_masks, which is
> > > > > defined only with CONFIG_PERF_REGS.
> > > > >
> > > > > In addition, perf record -I is only useful if the arch supports
> > > > > PERF_REGS. Hence, let's expose -I conditionally.
> > > > >
> > > > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> > > >
> > > > hum, I wonder why we have sample_reg_masks defined as weak in util/perf_regs.c
> > > > which is also built only via CONFIG_PERF_REGS
> > > >
> > > > I wonder we could get rid of the weak definition via attached patch, Stephane?
> > > >
> > > But the whole point of having it weak is to avoid this error scenario
> > > on any arch without support
> > > and avoid ugly #ifdef HAVE_ in generic files.
> > > 
> > > if perf_regs.c is compiled on PPC, then why do we get the undefined?
> > 
> > As Jiri Olsa pointed out, powerpc and many other architectures don't 
> > (yet) have support for perf regs.
> > 
> > But, the larger reason to introduce #ifdef is so the user doesn't see 
> > options (s)he can't use on a specific architecture, along the same lines 
> > as builtin-probe.c
> 
> Stephane, Arnaldo,
> Suka has also posted a fix for this with a different approach [1]. Can 
> you please ack/pull one of these versions? Building perf is broken on 
> v4.3-rc due to this.

I did not get any answer for additional comments I made to the patch
(couldnt get marc.info working, sending the patch again)

> 
> [1] http://article.gmane.org/gmane.linux.kernel/2046370

I dont have this last version, which seems to have other changes
and patch in above link looks mangled, could you please repost it?

thanks,
jirka


---
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 142eeb341b29..19c8fd22fbe3 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1082,9 +1082,11 @@ struct option __record_options[] = {
 		    "sample transaction flags (special events only)"),
 	OPT_BOOLEAN(0, "per-thread", &record.opts.target.per_thread,
 		    "use per-thread mmaps"),
+#ifdef HAVE_PERF_REGS_SUPPORT
 	OPT_CALLBACK_OPTARG('I', "intr-regs", &record.opts.sample_intr_regs, NULL, "any register",
 		    "sample selected machine registers on interrupt,"
 		    " use -I ? to list register names", parse_regs),
+#endif
 	OPT_BOOLEAN(0, "running-time", &record.opts.running_time,
 		    "Record running/enabled time of read (:S) events"),
 	OPT_CALLBACK('k', "clockid", &record.opts,
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 4bc7a9ab45b1..93c6371405a3 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -104,7 +104,7 @@ libperf-$(CONFIG_LIBBABELTRACE) += data-convert-bt.o
 
 libperf-y += scripting-engines/
 
-libperf-$(CONFIG_PERF_REGS) += perf_regs.o
+libperf-y += perf_regs.o
 libperf-$(CONFIG_ZLIB) += zlib.o
 libperf-$(CONFIG_LZMA) += lzma.o
 

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Naveen N. Rao]

On 2015/09/29 08:53AM, Jiri Olsa wrote:
> On Tue, Sep 29, 2015 at 11:06:17AM +0530, Naveen N. Rao wrote:
> > On 2015/09/24 10:15PM, Naveen N Rao wrote:
> > > On 2015/09/24 08:32AM, Stephane Eranian wrote:
> > > > On Thu, Sep 24, 2015 at 5:57 AM, Jiri Olsa <jolsa@redhat.com> wrote:
> > > > >
> > > > > On Thu, Sep 24, 2015 at 05:41:58PM +0530, Naveen N. Rao wrote:
> > > > > > perf build currently fails on powerpc:
> > > > > >
> > > > > >   LINK     perf
> > > > > > libperf.a(libperf-in.o):(.toc+0x120): undefined reference to
> > > > > > `sample_reg_masks'
> > > > > > libperf.a(libperf-in.o):(.toc+0x130): undefined reference to
> > > > > > `sample_reg_masks'
> > > > > > collect2: error: ld returned 1 exit status
> > > > > > make[1]: *** [perf] Error 1
> > > > > > make: *** [all] Error 2
> > > > > >
> > > > > > This is due to parse-regs-options.c using sample_reg_masks, which is
> > > > > > defined only with CONFIG_PERF_REGS.
> > > > > >
> > > > > > In addition, perf record -I is only useful if the arch supports
> > > > > > PERF_REGS. Hence, let's expose -I conditionally.
> > > > > >
> > > > > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
> > > > >
> > > > > hum, I wonder why we have sample_reg_masks defined as weak in util/perf_regs.c
> > > > > which is also built only via CONFIG_PERF_REGS
> > > > >
> > > > > I wonder we could get rid of the weak definition via attached patch, Stephane?
> > > > >
> > > > But the whole point of having it weak is to avoid this error scenario
> > > > on any arch without support
> > > > and avoid ugly #ifdef HAVE_ in generic files.
> > > > 
> > > > if perf_regs.c is compiled on PPC, then why do we get the undefined?
> > > 
> > > As Jiri Olsa pointed out, powerpc and many other architectures don't 
> > > (yet) have support for perf regs.
> > > 
> > > But, the larger reason to introduce #ifdef is so the user doesn't see 
> > > options (s)he can't use on a specific architecture, along the same lines 
> > > as builtin-probe.c
> > 
> > Stephane, Arnaldo,
> > Suka has also posted a fix for this with a different approach [1]. Can 
> > you please ack/pull one of these versions? Building perf is broken on 
> > v4.3-rc due to this.
> 
> I did not get any answer for additional comments I made to the patch
> (couldnt get marc.info working, sending the patch again)

Hi Jiri,
I concur with the changes you proposed to my patch here (getting rid of 
the weak variant):
http://article.gmane.org/gmane.linux.kernel/2046108

I am aware of the other approach you posted (and the one attached 
below). When I said "please ack/pull one of these versions", I meant one 
of: your version, Suka's and mine.

> 
> > 
> > [1] http://article.gmane.org/gmane.linux.kernel/2046370
> 
> I dont have this last version, which seems to have other changes
> and patch in above link looks mangled, could you please repost it?

Can you please check the raw version:
http://article.gmane.org/gmane.linux.kernel/2046370/raw


Thanks,
Naveen

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Jiri Olsa]

On Tue, Sep 29, 2015 at 01:30:10PM +0530, Naveen N. Rao wrote:

SNIP

> > > Suka has also posted a fix for this with a different approach [1]. Can 
> > > you please ack/pull one of these versions? Building perf is broken on 
> > > v4.3-rc due to this.
> > 
> > I did not get any answer for additional comments I made to the patch
> > (couldnt get marc.info working, sending the patch again)
> 
> Hi Jiri,
> I concur with the changes you proposed to my patch here (getting rid of 
> the weak variant):
> http://article.gmane.org/gmane.linux.kernel/2046108
> 
> I am aware of the other approach you posted (and the one attached 
> below). When I said "please ack/pull one of these versions", I meant one 
> of: your version, Suka's and mine.

I was hoping somebody could test it on ppc ;-)

I think the last version (in my last email) that keeps the weak
variable is correct, let's wait for Arnaldo to sort this out

> 
> > 
> > > 
> > > [1] http://article.gmane.org/gmane.linux.kernel/2046370
> > 
> > I dont have this last version, which seems to have other changes
> > and patch in above link looks mangled, could you please repost it?
> 
> Can you please check the raw version:
> http://article.gmane.org/gmane.linux.kernel/2046370/raw

we have __maybe_unused definition in tools/include/linux/compiler.h
why to redeclare it?

jirka

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Naveen N. Rao]

On 2015/09/29 12:47PM, Jiri Olsa wrote:
> On Tue, Sep 29, 2015 at 01:30:10PM +0530, Naveen N. Rao wrote:
> 
> SNIP
> 
> > > > Suka has also posted a fix for this with a different approach [1]. Can 
> > > > you please ack/pull one of these versions? Building perf is broken on 
> > > > v4.3-rc due to this.
> > > 
> > > I did not get any answer for additional comments I made to the patch
> > > (couldnt get marc.info working, sending the patch again)
> > 
> > Hi Jiri,
> > I concur with the changes you proposed to my patch here (getting rid of 
> > the weak variant):
> > http://article.gmane.org/gmane.linux.kernel/2046108
> > 
> > I am aware of the other approach you posted (and the one attached 
> > below). When I said "please ack/pull one of these versions", I meant one 
> > of: your version, Suka's and mine.
> 
> I was hoping somebody could test it on ppc ;-)
> 
> I think the last version (in my last email) that keeps the weak
> variable is correct, let's wait for Arnaldo to sort this out

I just tried it, but it fails. As Suka points out in his patch:
"Adding perf_regs.o to util/Build unconditionally, exposes a 
redefinition error for 'perf_reg_value()' function (due to the static 
inline version in util/perf_regs.h). So use #ifdef 
HAVE_PERF_REGS_SUPPORT' around that function."

- Naveen

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Jiri Olsa]

On Tue, Sep 29, 2015 at 10:01:36PM +0530, Naveen N. Rao wrote:
> On 2015/09/29 12:47PM, Jiri Olsa wrote:
> > On Tue, Sep 29, 2015 at 01:30:10PM +0530, Naveen N. Rao wrote:
> > 
> > SNIP
> > 
> > > > > Suka has also posted a fix for this with a different approach [1]. Can 
> > > > > you please ack/pull one of these versions? Building perf is broken on 
> > > > > v4.3-rc due to this.
> > > > 
> > > > I did not get any answer for additional comments I made to the patch
> > > > (couldnt get marc.info working, sending the patch again)
> > > 
> > > Hi Jiri,
> > > I concur with the changes you proposed to my patch here (getting rid of 
> > > the weak variant):
> > > http://article.gmane.org/gmane.linux.kernel/2046108
> > > 
> > > I am aware of the other approach you posted (and the one attached 
> > > below). When I said "please ack/pull one of these versions", I meant one 
> > > of: your version, Suka's and mine.
> > 
> > I was hoping somebody could test it on ppc ;-)
> > 
> > I think the last version (in my last email) that keeps the weak
> > variable is correct, let's wait for Arnaldo to sort this out
> 
> I just tried it, but it fails. As Suka points out in his patch:
> "Adding perf_regs.o to util/Build unconditionally, exposes a 
> redefinition error for 'perf_reg_value()' function (due to the static 
> inline version in util/perf_regs.h). So use #ifdef 
> HAVE_PERF_REGS_SUPPORT' around that function."

could you (or Suka) please reply in here with the patch?

thanks,
jirka

Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Sukadev Bhattiprolu]

Jiri Olsa [jolsa@redhat.com] wrote:
| > I just tried it, but it fails. As Suka points out in his patch:
| > "Adding perf_regs.o to util/Build unconditionally, exposes a 
| > redefinition error for 'perf_reg_value()' function (due to the static 
| > inline version in util/perf_regs.h). So use #ifdef 
| > HAVE_PERF_REGS_SUPPORT' around that function."
| 
| could you (or Suka) please reply in here with the patch?
Jiri,

Do you mean this patch? I was planning on pinging Arnaldo again in a
couple of days about this patch, since the powerpc build is broken.

Sukadev

---


>From d1171a4c34c6100ec8b663ddb803dd69ef3fb7ce Mon Sep 17 00:00:00 2001
From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Date: Thu, 24 Sep 2015 17:53:49 -0400
Subject: [PATCH] perf: Fix build break on powerpc due to sample_reg_masks

perf_regs.c does not get built on Powerpc as CONFIG_PERF_REGS is false.
So the weak definition for 'sample_regs_masks' doesn't get picked up.

Adding perf_regs.o to util/Build unconditionally, exposes a redefinition
error for 'perf_reg_value()' function (due to the static inline version
in util/perf_regs.h). So use #ifdef HAVE_PERF_REGS_SUPPORT' around that
function.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
---
 tools/perf/util/Build       | 2 +-
 tools/perf/util/perf_regs.c | 2 ++
 tools/perf/util/perf_regs.h | 4 ++++
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 349bc96..e5f18a2 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -17,6 +17,7 @@ libperf-y += levenshtein.o
 libperf-y += llvm-utils.o
 libperf-y += parse-options.o
 libperf-y += parse-events.o
+libperf-y += perf_regs.o
 libperf-y += path.o
 libperf-y += rbtree.o
 libperf-y += bitmap.o
@@ -103,7 +104,6 @@ libperf-$(CONFIG_LIBBABELTRACE) += data-convert-bt.o
 
 libperf-y += scripting-engines/
 
-libperf-$(CONFIG_PERF_REGS) += perf_regs.o
 libperf-$(CONFIG_ZLIB) += zlib.o
 libperf-$(CONFIG_LZMA) += lzma.o
 
diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
index 885e8ac..6b8eb13 100644
--- a/tools/perf/util/perf_regs.c
+++ b/tools/perf/util/perf_regs.c
@@ -6,6 +6,7 @@ const struct sample_reg __weak sample_reg_masks[] = {
 	SMPL_REG_END
 };
 
+#ifdef HAVE_PERF_REGS_SUPPORT
 int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
 {
 	int i, idx = 0;
@@ -29,3 +30,4 @@ out:
 	*valp = regs->cache_regs[id];
 	return 0;
 }
+#endif
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index 2984dcc..8dbdfeb 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -3,6 +3,10 @@
 
 #include <linux/types.h>
 
+#ifndef __maybe_unused
+#define __maybe_unused __attribute__((unused))
+#endif
+
 struct regs_dump;
 
 struct sample_reg {
-- 
1.8.3.1

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Re: [PATCH] perf record: Limit --intr-regs to platforms supporting PERF_REGS

[Jiri Olsa]

On Tue, Sep 29, 2015 at 11:10:02AM -0700, Sukadev Bhattiprolu wrote:

SNIP

>  
> diff --git a/tools/perf/util/perf_regs.c b/tools/perf/util/perf_regs.c
> index 885e8ac..6b8eb13 100644
> --- a/tools/perf/util/perf_regs.c
> +++ b/tools/perf/util/perf_regs.c
> @@ -6,6 +6,7 @@ const struct sample_reg __weak sample_reg_masks[] = {
>  	SMPL_REG_END
>  };
>  
> +#ifdef HAVE_PERF_REGS_SUPPORT
>  int perf_reg_value(u64 *valp, struct regs_dump *regs, int id)
>  {
>  	int i, idx = 0;
> @@ -29,3 +30,4 @@ out:
>  	*valp = regs->cache_regs[id];
>  	return 0;
>  }
> +#endif
> diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
> index 2984dcc..8dbdfeb 100644
> --- a/tools/perf/util/perf_regs.h
> +++ b/tools/perf/util/perf_regs.h
> @@ -3,6 +3,10 @@
>  
>  #include <linux/types.h>
>  
> +#ifndef __maybe_unused
> +#define __maybe_unused __attribute__((unused))
> +#endif
> +

would the linux/compiler.h include do instead?

otherwise I'd be ok with this

thanks,
jirka