linux-toradex.git/include/linux/compiler.h, branch tegra-9.12.15

module_param: add __same_type convenience wrapper for __builtin_types_compatible_p

2009-06-12T12:16:57+00:00

Impact: new API

__builtin_types_compatible_p() is a little awkward to use: it takes two
types rather than types or variables, and it's just damn long.

(typeof(type) == type, so this works on types as well as vars).

Signed-off-by: Rusty Russell

branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=y

2009-04-07T15:07:41+00:00

Fix the branch tracer barfing on comma statements within if ()
statements.

Signed-off-by: Ingo Molnar

branch tracer: Fix for enabling branch profiling makes sparse unusable

2009-04-07T15:07:40+00:00

One of the changes between kernels 2.6.28 and 2.6.29 is that a branch profiler
has been added for if() statements. Unfortunately this patch makes the sparse
output unusable with CONFIG_TRACE_BRANCH_PROFILING=y: when branch profiling is
enabled, sparse prints so much false positives that the real issues are no
longer visible. This behavior can be reproduced as follows:
* enable CONFIG_TRACE_BRANCH_PROFILING, e.g. by running make allyesconfig or
  make allmodconfig.
* run make C=2

Result: a huge number of the following sparse warnings.
...
include/linux/cpumask.h:547:2: warning: symbol '______r' shadows an earlier one
include/linux/cpumask.h:547:2: originally declared here
...

The patch below fixes this by disabling branch profiling while analyzing the
kernel code with sparse.

See also:
* http://lkml.org/lkml/2008/11/21/18
* http://bugzilla.kernel.org/show_bug.cgi?id=12925

Signed-off-by: Bart Van Assche 
Cc: Andrew Morton 
Cc: Steven Rostedt 
LKML-Reference: <200904051620.02311.bart.vanassche@gmail.com>
Signed-off-by: Ingo Molnar

tracing: optimization of branch tracer

2009-03-18T03:10:43+00:00

Impact: better performance for if branch tracer

Use an array to count the hit and misses of a conditional instead
of using another conditional. This cuts down on saturation of branch
predictions and increases performance of modern pipelined architectures.

Signed-off-by: Witold Baryluk 
Signed-off-by: Steven Rostedt

Sanitize gcc version header includes

2009-01-02T17:23:03+00:00

 - include the gcc version-dependent header files from the generic gcc
   header file, rather than the other way around (iow: don't make the
   non-gcc header file have to know about gcc versions)

 - don't include compiler-gcc4.h for gcc 5 (for whenever it gets
   released).  That's just confusing and made us do odd things in the
   gcc4 header file (testing that we really had version 4!)

 - generate the name from the __GNUC__ version directly, rather than
   having a mess of #if conditionals.

Signed-off-by: Linus Torvalds

trace: profile all if conditionals

2008-11-23T10:41:01+00:00

Impact: feature to profile if statements

This patch adds a branch profiler for all if () statements.
The results will be found in:

  /debugfs/tracing/profile_branch

For example:

   miss      hit    %        Function                  File              Line
 ------- ---------  -        --------                  ----              ----
       0        1 100 x86_64_start_reservations      head64.c             127
       0        1 100 copy_bootdata                  head64.c             69
       1        0   0 x86_64_start_kernel            head64.c             111
      32        0   0 set_intr_gate                  desc.h               319
       1        0   0 reserve_ebda_region            head.c               51
       1        0   0 reserve_ebda_region            head.c               47
       0        1 100 reserve_ebda_region            head.c               42
       0        0   X maxcpus                        main.c               165

Miss means the branch was not taken. Hit means the branch was taken.
The percent is the percentage the branch was taken.

This adds a significant amount of overhead and should only be used
by those analyzing their system.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

trace: consolidate unlikely and likely profiler

2008-11-23T10:39:56+00:00

Impact: clean up to make one profiler of like and unlikely tracer

The likely and unlikely profiler prints out the file and line numbers
of the annotated branches that it is profiling. It shows the number
of times it was correct or incorrect in its guess. Having two
different files or sections for that matter to tell us if it was a
likely or unlikely is pretty pointless. We really only care if
it was correct or not.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

trace: remove extra assign in branch check

2008-11-23T10:39:28+00:00

Impact: clean up of branch check

The unlikely/likely profiler does an extra assign of the f.line.
This is not needed since it is already calculated at compile time.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

trace: rename unlikely profiler to branch profiler

2008-11-12T21:27:58+00:00

Impact: name change of unlikely tracer and profiler

Ingo Molnar suggested changing the config from UNLIKELY_PROFILE
to BRANCH_PROFILING. I never did like the "unlikely" name so I
went one step farther, and renamed all the unlikely configurations
to a "BRANCH" variant.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

tracing: branch tracer, fix vdso crash

2008-11-12T12:26:38+00:00

Impact: fix bootup crash

the branch tracer missed arch/x86/vdso/vclock_gettime.c from
disabling tracing, which caused such bootup crashes:

  [  201.840097] init[1]: segfault at 7fffed3fe7c0 ip 00007fffed3fea2e sp 000077

also clean up the ugly ifdefs in arch/x86/kernel/vsyscall_64.c by
creating DISABLE_UNLIKELY_PROFILE facility for code to turn off
instrumentation on a per file basis.

Signed-off-by: Ingo Molnar