diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-11-23 15:42:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-11-23 18:18:31 +0100 |
| commit | 1b290d670ffa883b7e062177463a8efd00eaa2c1 (patch) | |
| tree | d6449227ae19be6fb9046ac5d12cc3ae9d252972 /tools/perf/Documentation | |
| parent | perf: Add kernel side syscall events support for breakpoints (diff) | |
| download | linux-1b290d670ffa883b7e062177463a8efd00eaa2c1.tar.xz linux-1b290d670ffa883b7e062177463a8efd00eaa2c1.zip | |
perf tools: Add support for breakpoint events in perf tools
Add the breakpoint events support with this new sysnopsis:
mem:addr[:access]
Where addr is a raw addr value in the kernel and access can be
either [r][w][x]
Example to profile tasklist_lock:
$ grep tasklist_lock /proc/kallsyms
ffffffff8189c000 D tasklist_lock
$ perf record -e mem:0xffffffff8189c000:rw -a -f -c 1
$ perf report
# Samples: 62
#
# Overhead Command Shared Object Symbol
# ........ ............... ............. ......
#
29.03% swapper [kernel] [k] _raw_read_trylock
29.03% swapper [kernel] [k] _raw_read_unlock
19.35% init [kernel] [k] _raw_read_trylock
19.35% init [kernel] [k] _raw_read_unlock
1.61% events/0 [kernel] [k] _raw_read_trylock
1.61% events/0 [kernel] [k] _raw_read_unlock
Coming soon:
- Support for symbols in the event definition.
- Default period to 1 for breakpoint events because these are
not high frequency events. The same thing is needed for trace
events.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
LKML-Reference: <1258987355-8751-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-record.txt | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt index 0ff23de9e453..fc46c0b40f6e 100644 --- a/tools/perf/Documentation/perf-record.txt +++ b/tools/perf/Documentation/perf-record.txt @@ -26,11 +26,19 @@ OPTIONS -e:: --event=:: - Select the PMU event. Selection can be a symbolic event name - (use 'perf list' to list all events) or a raw PMU - event (eventsel+umask) in the form of rNNN where NNN is a - hexadecimal event descriptor. + Select the PMU event. Selection can be: + - a symbolic event name (use 'perf list' to list all events) + + - a raw PMU event (eventsel+umask) in the form of rNNN where NNN is a + hexadecimal event descriptor. + + - a hardware breakpoint event in the form of '\mem:addr[:access]' + where addr is the address in memory you want to break in. + Access is the memory access type (read, write, execute) it can + be passed as follows: '\mem:addr[:[r][w][x]]'. + If you want to profile read-write accesses in 0x1000, just set + 'mem:0x1000:rw'. -a:: System-wide collection. |