<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/tools/perf/util/header.c, branch v3.4-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>perf tools: Fix various casting issues for 32 bits</title>
<updated>2012-03-22T18:11:18+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@redhat.com</email>
</author>
<published>2012-03-20T18:15:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9fafd98f1bf14276f95b69f0186ad5675f1e1a18'/>
<id>9fafd98f1bf14276f95b69f0186ad5675f1e1a18</id>
<content type='text'>
- util/parse-events.c(parse_events_add_breakpoint)
  need to use unsigned long instead of u64, otherwise
  we get following gcc error on 32 bits:
     error: cast from pointer to integer of different size

- util/header.c(print_event_desc)
  cannot retype to signed type, otherwise we get following
  gcc error on 32 bits:
     error: comparison between signed and unsigned integer expressions

Signed-off-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Corey Ashford &lt;cjashfor@linux.vnet.ibm.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Link: http://lkml.kernel.org/r/1332267341-26338-2-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
- util/parse-events.c(parse_events_add_breakpoint)
  need to use unsigned long instead of u64, otherwise
  we get following gcc error on 32 bits:
     error: cast from pointer to integer of different size

- util/header.c(print_event_desc)
  cannot retype to signed type, otherwise we get following
  gcc error on 32 bits:
     error: comparison between signed and unsigned integer expressions

Signed-off-by: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Corey Ashford &lt;cjashfor@linux.vnet.ibm.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;a.p.zijlstra@chello.nl&gt;
Link: http://lkml.kernel.org/r/1332267341-26338-2-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'perf/urgent' into perf/core</title>
<updated>2012-03-22T18:09:08+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2012-03-22T18:09:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0d09eb7a9a2ca4d7ed32f7b440bea78c0622814a'/>
<id>0d09eb7a9a2ca4d7ed32f7b440bea78c0622814a</id>
<content type='text'>
Merge Reason: to pick the fix:

 commit e7f01d1
     perf tools: Use scnprintf where applicable

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge Reason: to pick the fix:

 commit e7f01d1
     perf tools: Use scnprintf where applicable

Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Use scnprintf where applicable</title>
<updated>2012-03-14T15:36:19+00:00</updated>
<author>
<name>Arnaldo Carvalho de Melo</name>
<email>acme@redhat.com</email>
</author>
<published>2012-03-14T15:29:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e7f01d1e3d8d501deb8abeaa269d5d48a703b8b0'/>
<id>e7f01d1e3d8d501deb8abeaa269d5d48a703b8b0</id>
<content type='text'>
Several places were expecting that the value returned was the number of
characters printed, not what would be printed if there was space.

Fix it by using the scnprintf and vscnprintf variants we inherited from
the kernel sources.

Some corner cases where the number of printed characters were not
accounted were fixed too.

Reported-by: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Eric B Munson &lt;emunson@mgebm.net&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Mike Galbraith &lt;efault@gmx.de&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Yanmin Zhang &lt;yanmin_zhang@linux.intel.com&gt;
Cc: stable@kernel.org
Link: http://lkml.kernel.org/n/tip-kwxo2eh29cxmd8ilixi2005x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Several places were expecting that the value returned was the number of
characters printed, not what would be printed if there was space.

Fix it by using the scnprintf and vscnprintf variants we inherited from
the kernel sources.

Some corner cases where the number of printed characters were not
accounted were fixed too.

Reported-by: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Anton Blanchard &lt;anton@samba.org&gt;
Cc: Eric B Munson &lt;emunson@mgebm.net&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Frederic Weisbecker &lt;fweisbec@gmail.com&gt;
Cc: Mike Galbraith &lt;efault@gmx.de&gt;
Cc: Paul Mackerras &lt;paulus@samba.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Stephane Eranian &lt;eranian@google.com&gt;
Cc: Yanmin Zhang &lt;yanmin_zhang@linux.intel.com&gt;
Cc: stable@kernel.org
Link: http://lkml.kernel.org/n/tip-kwxo2eh29cxmd8ilixi2005x@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf record: Add HEADER_BRANCH_STACK tag</title>
<updated>2012-03-09T07:26:08+00:00</updated>
<author>
<name>Stephane Eranian</name>
<email>eranian@google.com</email>
</author>
<published>2012-03-08T22:47:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=330aa675b4f92a422cb6d3acbbfd16a628017520'/>
<id>330aa675b4f92a422cb6d3acbbfd16a628017520</id>
<content type='text'>
This patch adds a new feature bit, namely,
HEADER_BRANCH_STACK.  When present, it indicates
that sample records may contain branch stack.

This could be useful to a viewer to switch to
branch mode without having to parse all the
samples or without a specific cmdline option.

This will be used in a subsequent patch to
enhance perf report with branch stacks.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331246868-19905-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds a new feature bit, namely,
HEADER_BRANCH_STACK.  When present, it indicates
that sample records may contain branch stack.

This could be useful to a viewer to switch to
branch mode without having to parse all the
samples or without a specific cmdline option.

This will be used in a subsequent patch to
enhance perf report with branch stacks.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1331246868-19905-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Make perf able to read files from older ABIs</title>
<updated>2012-03-09T07:26:07+00:00</updated>
<author>
<name>Stephane Eranian</name>
<email>eranian@google.com</email>
</author>
<published>2012-02-09T22:21:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=114382a0aea97974803c942f106d462cbca5c64d'/>
<id>114382a0aea97974803c942f106d462cbca5c64d</id>
<content type='text'>
This patches provides a way to handle legacy perf.data
files.  Legacy files are those using the older PERFFILE
signature.

For those, it is still necessary to detect endianness but
without comparing their header-&gt;attr_size with the
tool's own version as it may be different. Instead, we use
a reference table for all known sizes from the legacy era.

We try all the combinations for sizes and endianness. If we find
a match, we proceed, otherwise we return: "incompatible file
format".

This is also done for the pipe-mode file format.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-19-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patches provides a way to handle legacy perf.data
files.  Legacy files are those using the older PERFFILE
signature.

For those, it is still necessary to detect endianness but
without comparing their header-&gt;attr_size with the
tool's own version as it may be different. Instead, we use
a reference table for all known sizes from the legacy era.

We try all the combinations for sizes and endianness. If we find
a match, we proceed, otherwise we return: "incompatible file
format".

This is also done for the pipe-mode file format.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-19-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Fix ABI compatibility bug in print_event_desc()</title>
<updated>2012-03-09T07:26:06+00:00</updated>
<author>
<name>Stephane Eranian</name>
<email>eranian@google.com</email>
</author>
<published>2012-02-09T22:21:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=62db90681c0db8c76e5db006b929a2edd5d12ae6'/>
<id>62db90681c0db8c76e5db006b929a2edd5d12ae6</id>
<content type='text'>
This patches cleans up local variable types for msz and ret.
They need to be size_t and ssize_t respectively.

It also fixes a bug whereby perf would not read attr struct
with a different size than what it knows about.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-18-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patches cleans up local variable types for msz and ret.
They need to be size_t and ssize_t respectively.

It also fixes a bug whereby perf would not read attr struct
with a different size than what it knows about.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-18-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Enable reading of perf.data files from different ABI rev</title>
<updated>2012-03-09T07:26:06+00:00</updated>
<author>
<name>Stephane Eranian</name>
<email>eranian@google.com</email>
</author>
<published>2012-02-09T22:21:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=69996df486fc3921bbaaa17fca0d68f537f9eabf'/>
<id>69996df486fc3921bbaaa17fca0d68f537f9eabf</id>
<content type='text'>
This patch allows perf to process perf.data files generated
using an ABI that has a different perf_event_attr struct size,
i.e., a different ABI version.

The perf_event_attr can be extended, yet perf needs to cope with
older perf.data files. Similarly, perf must be able to cope with
a perf.data file which is using a newer version of the ABI than
what it knows about.

This patch adds read_attr(), a routine that reads a
perf_event_attr struct from a file incrementally based on its
advertised size. If the on-file struct is smaller than what perf
knows, then the extra fields are zeroed. If the on-file struct
is bigger, then perf only uses what it knows about, the rest is
skipped.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-17-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch allows perf to process perf.data files generated
using an ABI that has a different perf_event_attr struct size,
i.e., a different ABI version.

The perf_event_attr can be extended, yet perf needs to cope with
older perf.data files. Similarly, perf must be able to cope with
a perf.data file which is using a newer version of the ABI than
what it knows about.

This patch adds read_attr(), a routine that reads a
perf_event_attr struct from a file incrementally based on its
advertised size. If the on-file struct is smaller than what perf
knows, then the extra fields are zeroed. If the on-file struct
is bigger, then perf only uses what it knows about, the rest is
skipped.

Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-17-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar &lt;mingo@elte.hu&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Factor out feature op to process header sections</title>
<updated>2012-02-14T01:33:36+00:00</updated>
<author>
<name>Robert Richter</name>
<email>robert.richter@amd.com</email>
</author>
<published>2012-02-10T14:41:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f1c67db7e351bf9fd328e368ba045cbeca11d513'/>
<id>f1c67db7e351bf9fd328e368ba045cbeca11d513</id>
<content type='text'>
There is individual code for each feature to process header sections.

Adding a function pointer .process to struct feature_ops for keeping the
implementation in separate functions. Code to process header sections is
now a generic function.

Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Link: http://lkml.kernel.org/r/1328884916-5901-2-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter &lt;robert.richter@amd.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
There is individual code for each feature to process header sections.

Adding a function pointer .process to struct feature_ops for keeping the
implementation in separate functions. Code to process header sections is
now a generic function.

Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Link: http://lkml.kernel.org/r/1328884916-5901-2-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter &lt;robert.richter@amd.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: Moving code in header.c</title>
<updated>2012-02-14T01:32:32+00:00</updated>
<author>
<name>Robert Richter</name>
<email>robert.richter@amd.com</email>
</author>
<published>2012-02-10T14:41:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=08d95bd256277f914e525aeb292da52f15173e7d'/>
<id>08d95bd256277f914e525aeb292da52f15173e7d</id>
<content type='text'>
Needed for later changes. No modified functionality.

Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Link: http://lkml.kernel.org/r/1328884916-5901-1-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter &lt;robert.richter@amd.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Needed for later changes. No modified functionality.

Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Link: http://lkml.kernel.org/r/1328884916-5901-1-git-send-email-robert.richter@amd.com
Signed-off-by: Robert Richter &lt;robert.richter@amd.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf tools: fix endianness detection in perf.data</title>
<updated>2012-02-09T14:28:10+00:00</updated>
<author>
<name>Stephane Eranian</name>
<email>eranian@google.com</email>
</author>
<published>2012-02-02T12:54:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=73323f541fe5f55a3b8a5c3d565bfc1efd64abf6'/>
<id>73323f541fe5f55a3b8a5c3d565bfc1efd64abf6</id>
<content type='text'>
The current version of perf detects whether or not the perf.data file is
written in a different endianness using the attr_size field in the
header of the file. This field represents sizeof(struct perf_event_attr)
as known to perf record. If the sizes do not match, then perf tries the
byte-swapped version. If they match, then the tool assumes a different
endianness.

The issue with the approach is that it assumes the size of
perf_event_attr always has to match between perf record and perf report.
However, the kernel perf_event ABI is extensible.  New fields can be
added to struct perf_event_attr. Consequently, it is not possible to use
attr_size to detect endianness.

This patch takes another approach by using the magic number written at
the beginning of the perf.data file to detect endianness. The magic
number is an eight-byte signature.  It's primary purpose is to identify
(signature) a perf.data file. But it could also be used to encode the
endianness.

The patch introduces a new value for this signature. The key difference
is that the signature is written differently in the file depending on
the endianness. Thus, by comparing the signature from the file with the
tool's own signature it is possible to detect endianness. The new
signature is "PERFILE2".

Backward compatiblity with existing perf.data file is ensured.

Tested-by: David Ahern &lt;dsahern@gmail.com&gt;
Acked-by: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Anshuman Khandual &lt;khandual@linux.vnet.ibm.com&gt;
Cc: Arun Sharma &lt;asharma@fb.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Lin Ming &lt;ming.m.lin@intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Roberto Agostino Vitillo &lt;ravitillo@lbl.gov&gt;
Cc: Robert Richter &lt;robert.richter@amd.com&gt;
Cc: Vince Weaver &lt;vweaver1@eecs.utk.edu&gt;
Link: http://lkml.kernel.org/r/1328187288-24395-15-git-send-email-eranian@google.com
Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
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<pre>
The current version of perf detects whether or not the perf.data file is
written in a different endianness using the attr_size field in the
header of the file. This field represents sizeof(struct perf_event_attr)
as known to perf record. If the sizes do not match, then perf tries the
byte-swapped version. If they match, then the tool assumes a different
endianness.

The issue with the approach is that it assumes the size of
perf_event_attr always has to match between perf record and perf report.
However, the kernel perf_event ABI is extensible.  New fields can be
added to struct perf_event_attr. Consequently, it is not possible to use
attr_size to detect endianness.

This patch takes another approach by using the magic number written at
the beginning of the perf.data file to detect endianness. The magic
number is an eight-byte signature.  It's primary purpose is to identify
(signature) a perf.data file. But it could also be used to encode the
endianness.

The patch introduces a new value for this signature. The key difference
is that the signature is written differently in the file depending on
the endianness. Thus, by comparing the signature from the file with the
tool's own signature it is possible to detect endianness. The new
signature is "PERFILE2".

Backward compatiblity with existing perf.data file is ensured.

Tested-by: David Ahern &lt;dsahern@gmail.com&gt;
Acked-by: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Anshuman Khandual &lt;khandual@linux.vnet.ibm.com&gt;
Cc: Arun Sharma &lt;asharma@fb.com&gt;
Cc: David Ahern &lt;dsahern@gmail.com&gt;
Cc: Ingo Molnar &lt;mingo@elte.hu&gt;
Cc: Lin Ming &lt;ming.m.lin@intel.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Roberto Agostino Vitillo &lt;ravitillo@lbl.gov&gt;
Cc: Robert Richter &lt;robert.richter@amd.com&gt;
Cc: Vince Weaver &lt;vweaver1@eecs.utk.edu&gt;
Link: http://lkml.kernel.org/r/1328187288-24395-15-git-send-email-eranian@google.com
Signed-off-by: Stephane Eranian &lt;eranian@google.com&gt;
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
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