diff options
| author | Dave Hansen <dave@linux.vnet.ibm.com> | 2008-10-15 22:01:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-16 11:21:31 -0700 |
| commit | 22b8ce94708f7cdf0b04965c6f7443dfd374c35c (patch) | |
| tree | e2d5b60e9b881cf251185b23c3853c8b3e52d42a /Documentation | |
| parent | 0c2d64fb6cae9aae480f6a46cfe79f8d7d48b59f (diff) | |
profiling: dynamically enable readprofile at runtime
Way too often, I have a machine that exhibits some kind of crappy
behavior. The CPU looks wedged in the kernel or it is spending way too
much system time and I wonder what is responsible.
I try to run readprofile. But, of course, Ubuntu doesn't enable it by
default. Dang!
The reason we boot-time enable it is that it takes a big bufffer that we
generally can only bootmem alloc. But, does it hurt to at least try and
runtime-alloc it?
To use:
echo 2 > /sys/kernel/profile
Then run readprofile like normal.
This should fix the compile issue with allmodconfig. I've compile-tested
on a bunch more configs now including a few more architectures.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-profiling | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-profiling b/Documentation/ABI/testing/sysfs-profiling new file mode 100644 index 00000000000..b02d8b8c173 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-profiling @@ -0,0 +1,13 @@ +What: /sys/kernel/profile +Date: September 2008 +Contact: Dave Hansen <dave@linux.vnet.ibm.com> +Description: + /sys/kernel/profile is the runtime equivalent + of the boot-time profile= option. + + You can get the same effect running: + + echo 2 > /sys/kernel/profile + + as you would by issuing profile=2 on the boot + command line. |