[PECL-DEV] [memcache/PECL] Performance problems with set & dataover 8KB

[BUSTARRET, Jean-Francois]

Just tested your script & the cvs version on a test server.

I don't have any problem at all. Performances degrades slowly with data size from 18416 set/s down to 2840 set/s.


> -----Message d'origine-----
> De : memcached-bounces at lists.danga.com 
> [mailto:memcached-bounces at lists.danga.com] De la part de 
> Mikael Johansson
> Envoyé : dimanche 23 avril 2006 22:34
> À : Pedram N.
> Cc : memcached at lists.danga.com; pecl-dev at lists.php.net
> Objet : Re: [PECL-DEV] [memcache/PECL] Performance problems 
> with set & dataover 8KB
> 
> When the problem occur it's a whole lot slower, more like:
> 
> 7168 bytes: 8680 set/s
> 8192 bytes: 25 set/s
> 
> When using 32kb the threshold would also be moved to around 
> 32kb and not 8kb 
> as with the default chunk size. You might try this script
> 
> ini_set('memcache.chunk_size', 32768);
> 
> $i = 0;
> $d = 1024;
> $c1 = 100;
> $c2 = 1000;
> 
> $key = md5(uniqid(''));
> $mmc = memcache_connect('localhost', 11211);
> 
> for ($j1=0; $j1<$c1; $j1++, $i+=$d) {
>  $value = str_repeat('a', $i);
> 
>  list ($m1, $s1) = explode(' ', microtime());
>  for ($j2=0; $j2<$c2; $j2++)
>   memcache_set($mmc, $key, $value);
>  list ($m2, $s2) = explode(' ', microtime());
> 
>  $sps = round(1 / ($s2 + $m2 - ($s1 + $m1)) * $c2);
>  print "$i bytes: $sps set/s \n";
> }
> 
> //Mikael
> 
> ----- Original Message ----- 
> From: "Pedram N." <zenstyle at gmail.com>
> To: "Mikael Johansson" <mikael at synd.info>; 
> <memcached at lists.danga.com>; 
> <pecl-dev at lists.php.net>
> Sent: Sunday, April 23, 2006 10:00 PM
> Subject: Re: [PECL-DEV] [memcache/PECL] Performance problems 
> with set & data 
> over 8KB
> 
> 
> When I run the test:
> 
> 6KB comes up very quick -- 12662 set/s 13269 get/s
> 7KB comes up very quick -- 12116 set/s 13017 get/s
> 8KB comes up very slow  --  9810 set/s 11953 get/s
> 9KB comes up even slower- 10212 set/s -1092 get/s
> 
> linux -- php 5.0.4 -- memcache2 w/ memcache.chunk_size = 32768
> 
> 
> On 4/23/06, Mikael Johansson <mikael at synd.info> wrote:
> > Setting the chunk size > 16k seem to mitigate the problem, 
> I've added an 
> > ini
> > config directive "memcache.chunk_size" for this purpose. Using
> > "memcache.chunk_size = 32768" in php.ini or 
> > "ini_set('memcache.chunk_size',
> > 32768);" should do the trick.
> >
> > The changes are in CVS, checking out a copy is as easy as:
> >
> >  cvs -d :pserver:cvsread at cvs.php.net:/repository login
> >  cvs -d :pserver:cvsread at cvs.php.net:/repository co pecl/memcache
> >
> > Would you mind checking to see that the problem does indeed 
> disappear with
> > larger chunk sizes in your environment?
> >
> > //Mikael
> >
> > ----- Original Message -----
> > From: "Antony Dovgal" <antony at zend.com>
> > To: "Mikael Johansson" <mikael at synd.info>
> > Cc: "Jean-François Bustarret" <jfbubus at gmail.com>;
> > <memcached at lists.danga.com>; <pecl-dev at lists.php.net>
> > Sent: Sunday, April 23, 2006 7:53 PM
> > Subject: Re: [PECL-DEV] [memcache/PECL] Performance 
> problems with set & 
> > data
> > over 8KB
> >
> >
> > > Probably this is somehow related to the problem I've met 
> in the past:
> > > 
> http://cvs.php.net/viewcvs.cgi/pecl/memcache/memcache.c?r1=1.8&r2=1.9
> > >
> > > The problem is that two subsequent writes to memcached 
> daemon are MUCH
> > > more slower than one writing the same data in one chunk.
> > >
> > > This was the reason why I had to patch PECL/memcache 2 
> years ago and 
> > > make
> > > it write the data and the delimiter ("\r\n") in one call.
> > > I don't remember details of the conversation I had with Brad and 
> > > Anatoly,
> > > but I still don't know the reasons of this behavior.
> >
> > --
> > PECL development discussion Mailing List (http://pecl.php.net/)
> > To unsubscribe, visit: http://www.php.net/unsub.php
> >
> >
> 
> 
> --
> 
> 
> 
> 
> ~~~
> 
> 
> 
>     This e-mail and any attachment thereto may contain 
> information which
>     is confidential and/or protected by intellectual property 
> rights and
>     are intended for the sole use of the recipient (s) named above.
>     Any use of the information contained herein ( including, but not
>     limited to, total or partial reproduction, communication or
>     distribution in any form) by other persons than the designated
>     recipient (s) is prohibited.
>     If  you have received this e-mail in error, please notify 
> the sender
>     either by telephone or by e-mail and delete the material from any
>     computer. 
> 
>