Re: Re: [Proposal] New Extension Yac (a user data cache base on shared memory without locks)

On Sat, Mar 23, 2013 at 7:00 AM, Laruence <laruence@php.net> wrote: > On Sat, Mar 23, 2013 at 6:31 PM, Terry Ellison <Terry@ellisons.org.uk> > wrote: > > On 23/03/13 09:46, Matīss Roberts Treinis 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/ > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > >