This patch creates a new script (compaction-times) to report time
spent in mm compaction. It is possible to report times in nanoseconds
(default) or microseconds (-u).
The option -p will break down results by process id, -pv will further
decompose by each compaction entry/exit.
For each compaction entry/exit what is reported is controlled by the
options:
-t report only timing
-m report migration stats
-ms report migration scanner stats
-fs report free scanner stats
The default is to report all.
Entries may be further filtered by pid, pid-range or comm (regex).
The script is useful when analysing workloads that compact memory. The
most common example will be THP allocations on systems with a lot of
uptime that has fragmented memory.
This is an example of using the script to analyse a thpscale from
mmtests which deliberately fragments memory and allocates THP in 4
separate threads
# Recording step, one of the following;
$ perf record -e 'compaction:mm_compaction_*' ./workload
# or:
$ perf script record compaction-times
# Reporting: basic
total: 2444505743ns migration: moved=357738 failed=39275
free_scanner: scanned=2705578 isolated=387875
migration_scanner: scanned=414426 isolated=397013
# Reporting: Per task stall times
$ perf script report compaction-times -- -t -p
total: 2444505743ns
6384[thpscale]: 740800017ns
6385[thpscale]: 274119512ns
6386[thpscale]: 832961337ns
6383[thpscale]: 596624877ns
# Reporting: Per-compaction attempts for task 6385
$ perf script report compaction-times -- -m -pv 6385
total: 274119512ns migration: moved=14893 failed=24285
6385[thpscale]: 274119512ns migration: moved=14893 failed=24285
6385[thpscale].1: 3033277ns migration: moved=511 failed=1
6385[thpscale].2: 9592094ns migration: moved=1524 failed=12
6385[thpscale].3: 2495587ns migration: moved=512 failed=0
6385[thpscale].4: 2561766ns migration: moved=512 failed=0
6385[thpscale].5: 2523521ns migration: moved=512 failed=0
..... output continues ...
Changes since v1:
- report stats for isolate_migratepages and isolate_freepages
(Vlastimil Babka)
- refactor code to achieve above
- add help text
- output to stdout/stderr explicitly
Signed-off-by: Tony Jones <tonyj@suse.com>
Cc: Mel Gorman <mgorman@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/1439840932-8933-1-git-send-email-tonyj@suse.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
84e5d89a77