Antony Mawer wrote:
On 28/01/2008 6:52 PM, Alexey Popov wrote:
The problem is that concurrent lstat()'s are very slow on FreeBSD now.
Possibly you can decrease the number of lstat() calls by tuning
realpath cache size in PHP. Just add "realpath_cache_size=512k" to
php.ini. However I'm not sure this cache is used in open_basedir.
See the following thread for details:
http://lists.freebsd.org/pipermail/freebsd-stable/2007-November/038371.html
... so how does one go about profiling lstat() to find out where the
source of the slowness originates from? Is pmc profiling the way to do
this?
The last thread on this topic (referenced above) seemed to point the
finger at the default value of vfs.ufs.dirhash_maxmem being too small...
which would suggest this is an inherit limitation in UFS(2?) and/or its
default tuning.
If you try increasing the amount of memory allocated for dirhash, does
this improve performance at all? eg:
# sysctl vfs.ufs.dirhash_maxmem=10240000
vfs.ufs.dirhash_maxmem: 2097152 -> 10240000
... and then re-run the benchmarks to see if this makes any noticeable
difference. The fact that it was indicated that Mac OS X also suffers
the same problems suggests this may be a VFS issue rather than UFS
specific...?
I tried sysctl vfs.ufs.dirhash_maxmem=10240000 and
realpath_cache_size=512k in php.ini and sysctl vfs.lookup_shared=1
but all without any significant impact on performance with open_basedir
enabled.
I also tried this patch for vfs_cache
http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/kern/vfs_cache.c.diff?r1=1.114;r2=1.115
but again without success.
top shows following CPU usage for synthetic test with PHP 5.2.5 on
7.0-BETA4 with SCHED_ULE an vfs_cache patch + both sysctl tunables and
php.ini directive:
CPU states: 8.1% user, 0.0% nice, 88.6% system, 0.2% interrupt, 3.2%
idle
Does somebody have any other ideas?
Miroslav Lachman
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