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| author | Avi Kivity <avi@redhat.com> | 2010-04-19 13:52:53 +0400 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-05-17 13:17:58 +0400 |
| commit | 9beeaa2d689842f7760aa16c512e6bb8182d38b6 (patch) | |
| tree | 62cea0772127c4b1c0b476e46dec6830d36809c1 /Documentation | |
| parent | 3246af0ece6c61689847417977733f0b12dc4b6f (diff) | |
| parent | a1645ce12adb6c9cc9e19d7695466204e3f017fe (diff) | |
| download | linux-9beeaa2d689842f7760aa16c512e6bb8182d38b6.tar.xz | |
Merge branch 'perf'
Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/kprobes.txt | 10 | ||||
| -rw-r--r-- | Documentation/trace/kprobetrace.txt | 4 |
2 files changed, 5 insertions, 9 deletions
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 2f9115c0ae62..61c291cddf18 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt @@ -165,8 +165,8 @@ the user entry_handler invocation is also skipped. 1.4 How Does Jump Optimization Work? -If you configured your kernel with CONFIG_OPTPROBES=y (currently -this option is supported on x86/x86-64, non-preemptive kernel) and +If your kernel is built with CONFIG_OPTPROBES=y (currently this flag +is automatically set 'y' on x86/x86-64, non-preemptive kernel) and the "debug.kprobes_optimization" kernel parameter is set to 1 (see sysctl(8)), Kprobes tries to reduce probe-hit overhead by using a jump instruction instead of a breakpoint instruction at each probepoint. @@ -271,8 +271,6 @@ tweak the kernel's execution path, you need to suppress optimization, using one of the following techniques: - Specify an empty function for the kprobe's post_handler or break_handler. or -- Config CONFIG_OPTPROBES=n. - or - Execute 'sysctl -w debug.kprobes_optimization=n' 2. Architectures Supported @@ -307,10 +305,6 @@ it useful to "Compile the kernel with debug info" (CONFIG_DEBUG_INFO), so you can use "objdump -d -l vmlinux" to see the source-to-object code mapping. -If you want to reduce probing overhead, set "Kprobes jump optimization -support" (CONFIG_OPTPROBES) to "y". You can find this option under the -"Kprobes" line. - 4. API Reference The Kprobes API includes a "register" function and an "unregister" diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index a9100b28eb84..ec94748ae65b 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -40,7 +40,9 @@ Synopsis of kprobe_events $stack : Fetch stack address. $retval : Fetch return value.(*) +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**) - NAME=FETCHARG: Set NAME as the argument name of FETCHARG. + NAME=FETCHARG : Set NAME as the argument name of FETCHARG. + FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types + (u8/u16/u32/u64/s8/s16/s32/s64) are supported. (*) only for return probe. (**) this is useful for fetching a field of data structures. |