[PECL-DEV] [Proposal] New Extension Yac (a user data cache base on shared memory without locks) View as Markdown

Le 23/03/2013 12:00, Laruence a écrit :

and to be honest,  I think user data cache and opcodes cache

should be separated into different modules..

Big +1

On Sat, Mar 23, 2013 at 6:31 PM, Terry Ellison Terry@ellisons.org.uk
wrote:

Memcached is distributed caching system, where as APC's user data
cache is not. Memcached requires separate server instance (memcached)
to operate. APC does not.

Yes, but there is nothing to stop an admin of an application-dedicated
system or VM configuring and using an in-server memcached.

Also, APC's user cache is 5+ times faster
than memcached. If some extension is to provide this functionality, it
has to be as close as possible in possibilities and speed as APC's
implementation has. Memcached is not and never hasn't been an
alternative for APC, they are meant for two different jobs.

I also agree that memcache is slower because it is out of process and
that
for some usecases the relative speed differences due to these context
switches will impact application performance. Yes, they have different
sweet-spots and operational characteristics, but for many usecases the
relative impact will be immaterial, and memcached can be a perfectly
acceptable substitute.

Applications which are closely coupled to high APC data cache usage will
probably stay with APC for the foreseeable future.
Hey:
APC is not a pure user data cache, the user data cache of it is a
additional function of opcodes cache, that means the implemention is
restricted by opcodes cache context.

and to be honest,  I think user data cache and opcodes cache

should be separated into different modules..

Yac is a pure user data cache, doesn't have the restriction which

APC has, that is why Yac can be implemented without locks.

you can see a big performance improvement compare Yac against APC,

http://www.laruence.com/2013/03/18/2846.html (use google translate,
if you can not read chinese :))

thanks

+1 from me too :)

An SMA-based data cache would be a useful adjunct to O+, so I will be
interested in this, but I just don't see this filling a show-stopper gap
that must be addressed as a priority.

<snip>

Laurence, you are correct that O+ doesn't provide data caching, but what
about memcached and the PECL packages that support it?
http://pecl.php.net/package/memcache and
http://pecl.php.net/package/memcached

--
Laruence Xinchen Hui
http://www.laruence.com/