Re: [PHP] Including files on NFS mount slow with APC enabled

Hi,

APC checks by default if every included file was modified doing a stat
call. You can disable it, setting apc.stat to 0
(http://www.php.net/manual/en/apc.configuration.php#ini.apc.stat). Try
if that improves the performance. Of course, you should manually
delete the APC opcode cache every time you modify a PHP file, since
APC won't detect that it was modified.

Regards,

Jonathan

On Mon, Aug 16, 2010 at 10:21 AM, Mark Hunting <[email protected]> wrote:
> I am struggling with the performance of some websites that use a lot of
> includes (using include_once). The files are on a NFS mount (NFSv4), and
> I use APC to speed things up. APC has enough memory, and I see all
> included files are in the APC cache. apc.include_once_override is
> enabled. This is on a Ubuntu Linux 10.04 server.
>
> What surprises me is that using strace I see apache open()ing all
> included files. I would think this is not necessary as APC has these
> files in its cache. Opening a file takes 1-3 ms, the websites include
> 100-200 files, so this costs about half a second for each request. I
> tried a lot to prevent this but my options are exhausted. Is it normal
> that all these files are open()ed each time, and if so how can I speed
> up these includes?
>
> Part of the trace is below, look especially at the first line where 2ms
> are lost while this file is in the APC cache:
>
> open("/[removed]/library/Zend/Application.php", O_RDONLY) = 1440 <0.002035>
> fstat(1440, {st_mode=S_IFREG|0755, st_size=11365, ...}) = 0 <0.000137>
> fstat(1440, {st_mode=S_IFREG|0755, st_size=11365, ...}) = 0 <0.000124>
> fstat(1440, {st_mode=S_IFREG|0755, st_size=11365, ...}) = 0 <0.000133>
> mmap(NULL, 11365, PROT_READ, MAP_SHARED, 1440, 0) = 0x7faf3f068000
> <0.000395>
> stat("/[removed]/library/Zend/Application.php", {st_mode=S_IFREG|0755,
> st_size=11365, ...}) = 0 <0.000219>
> munmap(0x7faf3f068000, 11365)           = 0 <0.000151>
> close(1440)                             = 0 <0.000845>
>
> Thanks,
> Mark
>
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