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Arnaldo Carvalho de Melo 218d61110f perf top: Do not use overwrite mode by default
Enabling --overwrite mode allows us to to use just the most recent
records, which helps in high core count machines such as Knights
Landing/Mill, but right now is being disabled by default as the pausing
used in this technique is leading to loss of metadata events such as
PERF_RECORD_MMAP which makes 'perf top' unable to resolve samples,
leading to lots of unknown samples appearing on the UI.

Enabling this may be useful if you are in such machines and profiling a
workload that doesn't creates short lived threads and/or doesn't uses
many executable mmap operations.

Work is being planed to solve this situation, till then, this will
remain disabled by default.

Reported-by: David Miller <davem@davemloft.net>
Acked-by: Kan Liang <kan.liang@intel.com>
Link: https://lkml.kernel.org/r/4f84468f-37d9-cf1b-12c1-514ef74b6a48@linux.intel.com
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: ebebbf0823 ("perf top: Switch default mode to overwrite mode")
Link: https://lkml.kernel.org/n/tip-ehvf77vi1si9409r7p4wx788@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2018-10-31 09:57:31 -03:00
..
Build.txt perf build: Add build documentation 2015-02-12 17:53:00 -03:00
Makefile perf Documentation: Fix out-of-tree asciidoctor man page generation 2018-09-18 10:17:16 -03:00
android.txt perf tools: Update android build documentation 2016-07-04 20:27:27 -03:00
asciidoc.conf perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
asciidoctor-extensions.rb perf Documentation: Support for asciidoctor 2018-04-26 13:47:10 -03:00
build-xed.txt perf script: Add --insn-trace for instruction decoding 2018-10-24 15:29:50 -03:00
callchain-overhead-calculation.txt perf tools: Document --children option in more detail 2015-04-29 10:38:06 -03:00
examples.txt perf record: Remove -f/--force option 2013-07-08 17:37:25 -03:00
intel-bts.txt perf tools: Add Intel BTS support 2015-08-21 11:34:10 -03:00
intel-pt.txt perf scripts python: call-graph-from-sql.py: Rename to exported-sql-viewer.py 2018-10-23 14:26:44 -03:00
itrace.txt perf script: Make itrace script default to all calls 2018-10-24 15:29:54 -03:00
jit-interface.txt perf symbols: Add description of JIT interface 2012-08-13 14:55:02 -03:00
jitdump-specification.txt perf jit: Add jitdump format specification document 2016-10-24 11:07:41 -03:00
manpage-1.72.xsl perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
manpage-base.xsl perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
manpage-bold-literal.xsl perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
manpage-normal.xsl perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
manpage-suppress-sp.xsl perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
perf-annotate.txt perf annotate: Add --percent-type option 2018-08-08 15:55:53 -03:00
perf-archive.txt perf archive: Remove duplicated 'runs' in man page 2013-12-09 15:21:45 -03:00
perf-bench.txt perf bench mem: Rename 'routine' to 'function' 2015-10-19 16:10:25 -03:00
perf-buildid-cache.txt perf buildid-cache: Support --purge-all option 2018-04-26 09:30:26 -03:00
perf-buildid-list.txt perf report: Accept fifos as input file 2011-12-23 17:01:03 -02:00
perf-c2c.txt perf c2c record: Record physical addresses in samples 2018-03-16 13:52:57 -03:00
perf-config.txt perf annotate: Allow setting the offset level in .perfconfig 2018-04-13 10:00:05 -03:00
perf-data.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-diff.txt perf diff: Add -q/--quiet option 2017-02-20 11:47:08 -03:00
perf-evlist.txt perf evlist: Document missing --force option 2017-11-16 14:50:07 -03:00
perf-ftrace.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-help.txt perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/ 2009-06-06 20:33:43 +02:00
perf-inject.txt perf inject: Document missing options 2017-11-16 14:50:05 -03:00
perf-kallsyms.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-kmem.txt perf kmem: Document a missing option & an argument 2018-02-16 14:55:42 -03:00
perf-kvm.txt perf tools: Configurable per thread proc map processing time out 2015-06-19 18:27:13 -03:00
perf-list.txt perf list: Add missing documentation for --desc and --debug options 2018-07-24 14:49:57 -03:00
perf-lock.txt perf lock: Document missing options 2017-11-16 14:50:04 -03:00
perf-mem.txt perf mem: Document incorrect and missing options 2018-04-23 11:59:18 -03:00
perf-probe.txt perf probe: Support escaped character in parser 2017-12-27 12:15:55 -03:00
perf-record.txt perf, tools: Use correct articles in comments 2018-07-16 00:21:03 +02:00
perf-report.txt perf report: Add --percent-type option 2018-08-08 15:55:54 -03:00
perf-sched.txt perf sched: Fix documentation for timehist 2018-04-12 10:33:36 -03:00
perf-script-perl.txt perf tools: Correct title markers for asciidoctor 2018-03-07 10:26:32 -03:00
perf-script-python.txt perf script python: Add dict fields introduction to Documentation 2018-06-06 15:40:10 -03:00
perf-script.txt perf script: Implement --graph-function 2018-10-24 15:29:55 -03:00
perf-stat.txt perf stat: Add --interval-clear option 2018-06-07 15:53:36 -03:00
perf-test.txt perf test: Add -F/--dont-fork option 2016-06-30 18:27:45 -03:00
perf-timechart.txt perf timechart: Document missing --force option 2017-11-16 14:50:06 -03:00
perf-top.txt perf top: Do not use overwrite mode by default 2018-10-31 09:57:31 -03:00
perf-trace.txt perf trace: Introduce per-event maximum number of events property 2018-10-22 14:27:12 -03:00
perf-version.txt perf version: Add man page 2018-04-02 13:52:23 -03:00
perf.data-file-format.txt perf tools: Fix perf.data format description of NRCPUS header 2018-05-30 15:40:26 -03:00
perf.txt perf tools: Handle -h and -v options 2015-10-05 16:36:18 -03:00
perfconfig.example perf config: Show default report configuration in example and docs 2016-09-01 09:44:13 -03:00
tips.txt perf c2c: Add a tip about cacheline events 2017-12-05 15:43:55 -03:00