[GIT PULL 0/8] perf/core improvements and fixes

[GIT PULL 0/8] perf/core improvements and fixes

[Arnaldo Carvalho de Melo]

Hi Ingo,

	Please consider pulling.

- Arnaldo

BTW.: There are several outstanding patchkits needing review and processing,
I'll be out this week for a conference, will try and speed up processing next
week.

The following changes since commit 0e537fef24d64f7bf3ef61a27edf64a8d9a5424c:

  Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core (2015-10-08 10:52:44 +0200)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-core-for-mingo

for you to fetch changes up to 3a70fcd3a4db56731f67f0189514953c74257944:

  tools build: Fix cross compile build (2015-10-13 11:59:43 -0300)

----------------------------------------------------------------
perf/core improvements and fixes:

User visible:

- Use the alternative with the most descriptive filename containing
  a vmlinux file for a given build-id, providing a better title line
  for tools such as 'annotate' (Arnaldo Carvalho de Melo)

- Remove help messages about previous right and left arrow keybidings, that
  were repurposed for horizontal scrolling (Arnaldo Carvalho de Melo)

- Inform how to reset the symbol filter in the hists browser (top & report)
  (Arnaldo Carvalho de Melo)

- Add 'm' key for context menu display in the hists browser, that became
  inacessible with the repurposing of the right arrow key for horizontal
  scrolling (Namhyung Kim)

- Use debug_frame for callchains if eh_frame is unusable (Rabin Vicent)

Build fixes:

- Fix strict-aliasing breakage with gcc 4.4 in the READ_ONCE/WRITE_ONCE code
  adopted from the kernel tree, that builds with -fno-strict-aliasing while
  tools/perf/ uses -Wstrict-aliasing=3 (Jiri Olsa)

- Fix unw_word_t pointer casts in code using libunwind for callchains,
  fixing the build in at least 32-bit MIPS systems (Rabin Vicent)

- Workaround cross compile build problems related to fixdep (Jiri Olsa)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

----------------------------------------------------------------
Arnaldo Carvalho de Melo (3):
      perf symbols: Try the .debug/ DSO cache as a last resort
      perf ui browsers: Remove help messages about use of right and arrow keys
      perf hists browser: Inform how to reset the symbol filter

Jiri Olsa (2):
      tools include: Fix strict-aliasing rules breakage
      tools build: Fix cross compile build

Namhyung Kim (1):
      perf hists browser: Add 'm' key for context menu display

Rabin Vincent (2):
      perf callchain: Use debug_frame if eh_frame is unusable
      perf callchains: Fix unw_word_t pointer casts

 tools/build/Makefile.include       |  4 ++++
 tools/include/linux/compiler.h     | 32 ++++++++++++++++++++++++--------
 tools/perf/ui/browsers/annotate.c  |  6 +++---
 tools/perf/ui/browsers/hists.c     | 13 ++++++++-----
 tools/perf/ui/browsers/map.c       |  2 +-
 tools/perf/ui/browsers/scripts.c   |  2 +-
 tools/perf/util/symbol.c           | 18 +++++++++---------
 tools/perf/util/unwind-libunwind.c | 14 ++++++++------
 8 files changed, 58 insertions(+), 33 deletions(-)

[PATCH 7/8] tools include: Fix strict-aliasing rules breakage

[Arnaldo Carvalho de Melo]

From: Jiri Olsa <jolsa@redhat.com>

Vinson reported build breakage with gcc 4.4 due to strict-aliasing.

   CC       util/annotate.o
 cc1: warnings being treated as errors
 util/annotate.c: In function ‘disasm__purge’:
 linux-next/tools/include/linux/compiler.h:66: error: dereferencing
 pointer ‘res.41’ does break strict-aliasing rules

The reason is READ_ONCE/WRITE_ONCE code we took from kernel sources.  They
intentionaly break aliasing rules. While this is ok for kernel because it's
built with -fno-strict-aliasing, it breaks perf which is build with
-Wstrict-aliasing=3.

Using extra __may_alias__ type to allow aliasing in this case.

Reported-and-tested-by: Vinson Lee <vlee@twopensource.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Martin Liska <mliska@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rabin Vincent <rabin@rab.in>
Cc: linux-next@vger.kernel.org
Link: http://lkml.kernel.org/r/20151013085214.GB2705@krava.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/include/linux/compiler.h | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index 9098083869c8..fa7208a32d76 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -43,13 +43,29 @@
 
 #include <linux/types.h>
 
+/*
+ * Following functions are taken from kernel sources and
+ * break aliasing rules in their original form.
+ *
+ * While kernel is compiled with -fno-strict-aliasing,
+ * perf uses -Wstrict-aliasing=3 which makes build fail
+ * under gcc 4.4.
+ *
+ * Using extra __may_alias__ type to allow aliasing
+ * in this case.
+ */
+typedef __u8  __attribute__((__may_alias__))  __u8_alias_t;
+typedef __u16 __attribute__((__may_alias__)) __u16_alias_t;
+typedef __u32 __attribute__((__may_alias__)) __u32_alias_t;
+typedef __u64 __attribute__((__may_alias__)) __u64_alias_t;
+
 static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
 {
 	switch (size) {
-	case 1: *(__u8 *)res = *(volatile __u8 *)p; break;
-	case 2: *(__u16 *)res = *(volatile __u16 *)p; break;
-	case 4: *(__u32 *)res = *(volatile __u32 *)p; break;
-	case 8: *(__u64 *)res = *(volatile __u64 *)p; break;
+	case 1: *(__u8_alias_t  *) res = *(volatile __u8_alias_t  *) p; break;
+	case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break;
+	case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break;
+	case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break;
 	default:
 		barrier();
 		__builtin_memcpy((void *)res, (const void *)p, size);
@@ -60,10 +76,10 @@ static __always_inline void __read_once_size(const volatile void *p, void *res,
 static __always_inline void __write_once_size(volatile void *p, void *res, int size)
 {
 	switch (size) {
-	case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
-	case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
-	case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
-	case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
+	case 1: *(volatile  __u8_alias_t *) p = *(__u8_alias_t  *) res; break;
+	case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break;
+	case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break;
+	case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break;
 	default:
 		barrier();
 		__builtin_memcpy((void *)p, (const void *)res, size);
-- 
2.1.0

Re: [GIT PULL 0/8] perf/core improvements and fixes

[Ingo Molnar]

* Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Hi Ingo,
> 
> 	Please consider pulling.
> 
> - Arnaldo
> 
> BTW.: There are several outstanding patchkits needing review and processing,
> I'll be out this week for a conference, will try and speed up processing next
> week.
> 
> The following changes since commit 0e537fef24d64f7bf3ef61a27edf64a8d9a5424c:
> 
>   Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core (2015-10-08 10:52:44 +0200)
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-core-for-mingo
> 
> for you to fetch changes up to 3a70fcd3a4db56731f67f0189514953c74257944:
> 
>   tools build: Fix cross compile build (2015-10-13 11:59:43 -0300)
> 
> ----------------------------------------------------------------
> perf/core improvements and fixes:
> 
> User visible:
> 
> - Use the alternative with the most descriptive filename containing
>   a vmlinux file for a given build-id, providing a better title line
>   for tools such as 'annotate' (Arnaldo Carvalho de Melo)
> 
> - Remove help messages about previous right and left arrow keybidings, that
>   were repurposed for horizontal scrolling (Arnaldo Carvalho de Melo)
> 
> - Inform how to reset the symbol filter in the hists browser (top & report)
>   (Arnaldo Carvalho de Melo)
> 
> - Add 'm' key for context menu display in the hists browser, that became
>   inacessible with the repurposing of the right arrow key for horizontal
>   scrolling (Namhyung Kim)
> 
> - Use debug_frame for callchains if eh_frame is unusable (Rabin Vicent)
> 
> Build fixes:
> 
> - Fix strict-aliasing breakage with gcc 4.4 in the READ_ONCE/WRITE_ONCE code
>   adopted from the kernel tree, that builds with -fno-strict-aliasing while
>   tools/perf/ uses -Wstrict-aliasing=3 (Jiri Olsa)
> 
> - Fix unw_word_t pointer casts in code using libunwind for callchains,
>   fixing the build in at least 32-bit MIPS systems (Rabin Vicent)
> 
> - Workaround cross compile build problems related to fixdep (Jiri Olsa)
> 
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> ----------------------------------------------------------------
> Arnaldo Carvalho de Melo (3):
>       perf symbols: Try the .debug/ DSO cache as a last resort
>       perf ui browsers: Remove help messages about use of right and arrow keys
>       perf hists browser: Inform how to reset the symbol filter
> 
> Jiri Olsa (2):
>       tools include: Fix strict-aliasing rules breakage
>       tools build: Fix cross compile build
> 
> Namhyung Kim (1):
>       perf hists browser: Add 'm' key for context menu display
> 
> Rabin Vincent (2):
>       perf callchain: Use debug_frame if eh_frame is unusable
>       perf callchains: Fix unw_word_t pointer casts
> 
>  tools/build/Makefile.include       |  4 ++++
>  tools/include/linux/compiler.h     | 32 ++++++++++++++++++++++++--------
>  tools/perf/ui/browsers/annotate.c  |  6 +++---
>  tools/perf/ui/browsers/hists.c     | 13 ++++++++-----
>  tools/perf/ui/browsers/map.c       |  2 +-
>  tools/perf/ui/browsers/scripts.c   |  2 +-
>  tools/perf/util/symbol.c           | 18 +++++++++---------
>  tools/perf/util/unwind-libunwind.c | 14 ++++++++------
>  8 files changed, 58 insertions(+), 33 deletions(-)

Pulled, thanks a lot Arnaldo!

	Ingo