linux/tools/perf
Ian Munsie 21ef97f05a perf session: Fallback to unordered processing if no sample_id_all
If we are running the new perf on an old kernel without support for
sample_id_all, we should fall back to the old unordered processing of
events. If we didn't than we would *always* process events without
timestamps out of order, whether or not we hit a reordering race. In
other words, instead of there being a chance of not attributing samples
correctly, we would guarantee that samples would not be attributed.

While processing all events without timestamps before events with
timestamps may seem like an intuitive solution, it falls down as
PERF_RECORD_EXIT events would also be processed before any samples.
Even with a workaround for that case, samples before/after an exec would
not be attributed correctly.

This patch allows commands to indicate whether they need to fall back to
unordered processing, so that commands that do not care about timestamps
on every event will not be affected. If we do fallback, this will print
out a warning if report -D was invoked.

This patch adds the test in perf_session__new so that we only need to
test once per session. Commands that do not use an event_ops (such as
record and top) can simply pass NULL in it's place.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <1291951882-sup-6069@au1.ibm.com>
Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-12-21 20:17:51 -02:00
..
arch Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 09:30:52 -07:00
bench perf bench: Add feature that measures the performance of the arch/x86/lib/memcpy_64.S memcpy routines via 'perf bench mem' 2010-11-26 08:15:57 +01:00
Documentation perf report: Allow user to specify path to kallsyms file 2010-12-09 11:07:07 -02:00
scripts perf: Rename 'perf trace' to 'perf script' 2010-11-16 19:37:44 +01:00
util perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
.gitignore perf tools: .gitignore += config.make config.make.autogen 2010-06-17 10:24:31 -03:00
builtin-annotate.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-bench.c perf options: Type check all the remaining OPT_ variants 2010-05-17 16:22:41 -03:00
builtin-buildid-cache.c perf buildid: add perfconfig option to specify buildid cache dir 2010-06-05 09:34:04 -03:00
builtin-buildid-list.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-diff.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-help.c perf options: Type check all the remaining OPT_ variants 2010-05-17 16:22:41 -03:00
builtin-inject.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-kmem.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-kvm.c perf options: Type check all the remaining OPT_ variants 2010-05-17 16:22:41 -03:00
builtin-list.c perf list: Fix large list output by using the pager 2009-08-13 09:05:48 +02:00
builtin-lock.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-probe.c perf probe: Add basic module support 2010-10-21 16:11:44 -02:00
builtin-record.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-report.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-sched.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-script.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-stat.c perf stat: Add csv-style output 2010-12-01 19:47:41 -02:00
builtin-test.c perf options: Type check OPT_BOOLEAN and fix the offenders 2010-05-17 16:22:37 -03:00
builtin-timechart.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin-top.c perf session: Fallback to unordered processing if no sample_id_all 2010-12-21 20:17:51 -02:00
builtin.h perf: Rename 'perf trace' to 'perf script' 2010-11-16 19:37:44 +01:00
command-list.txt Merge branch 'perf/rename' into perf/core 2010-12-01 09:22:19 +01:00
CREDITS perf_counter tools: Add CREDITS file for Git contributors 2009-06-24 19:54:29 +02:00
design.txt perf: Fix few typos + cosmetics 2010-01-13 17:39:44 +01:00
feature-tests.mak perf tools: Remove hardcoded include paths for elfutils 2010-11-19 16:38:04 -02:00
Makefile perf makefile: Allow strong and weak functions in LIB_OBJS 2010-12-07 11:58:50 -02:00
MANIFEST perf packaging: add memcpy to perf MANIFEST 2010-11-30 23:00:10 -02:00
perf-archive.sh perf buildid: add perfconfig option to specify buildid cache dir 2010-06-05 09:34:04 -03:00
perf.c perf: Rename 'perf trace' to 'perf script' 2010-11-16 19:37:44 +01:00
perf.h perf, MIPS: Support cross compiling of tools/perf for MIPS 2010-10-12 13:34:37 +02:00