linux/tools
Naoya Horiguchi d9b2ddf807 tools/vm/page-types.c: avoid memset() in walk_pfn() when count == 1
I found that page-types is very slow and my testing shows many timeout
errors.  Here's an example with a simple program allocating 1000 thps.

  $ time ./page-types -p $(pgrep -f test_alloc)
  ...
  real    0m17.201s
  user    0m16.889s
  sys     0m0.312s

Most of time is spent in memset().  Currently memset() clears over whole
buffer for every walk_pfn() call, which is inefficient when walk_pfn()
is called from walk_vma(), because in that case walk_pfn() is called for
each pfn.  So this patch limits the zero initialization only for the
first element.

  $ time ./page-types.patched -p $(pgrep -f test_alloc)
  ...
  real    0m0.182s
  user    0m0.046s
  sys     0m0.135s

Fixes: 954e95584579 ("tools/vm/page-types.c: add memory cgroup dumping and filtering")
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Suggested-by: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
..
arch
build tools build: Use .s extension for preprocessed assembler code 2016-03-03 11:10:37 -03:00
cgroup
firewire
hv tools: hv: vss: fix the write()'s argument: error -> vss_msg 2015-12-14 19:15:05 -08:00
iio iio: generic_buffer: be helpful about enabling channels 2015-08-16 10:51:26 +01:00
include tools: Make list.h self-sufficient 2016-01-12 12:42:07 -03:00
laptop/freefall
lguest tools/lguest: Clean up include dir 2015-08-26 06:12:35 +02:00
lib Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-14 17:58:53 -07:00
net tools/net: Use include/uapi with __EXPORTED_HEADERS__ 2015-11-15 17:24:33 -05:00
nfsd
perf mm, tracing: unify mm flags handling in tracepoints and printk 2016-03-15 16:55:16 -07:00
power Power management and ACPI material for v4.6-rc1, part 1 2016-03-16 14:10:53 -07:00
scripts tools: Move Makefile.arch from perf/config to tools/scripts 2016-01-11 19:22:20 -03:00
spi spi: spidev_test: Fix typo in error message 2015-12-08 17:58:56 +00:00
testing libnvdimm for 4.6 2016-03-16 17:45:56 -07:00
thermal/tmon tools/thermal: tmon: use pkg-config also for CFLAGS 2015-10-10 11:32:31 +08:00
time
usb usb: patches for v4.4 merge window 2015-10-22 17:19:33 -07:00
virtio tools/virtio: add ringtest utilities 2016-01-26 10:18:30 +02:00
vm tools/vm/page-types.c: avoid memset() in walk_pfn() when count == 1 2016-03-17 15:09:34 -07:00
Makefile Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-01-14 11:39:09 -08:00