Re: [users@httpd] performance prob due to httpd's piling up

Bennett Haselton <bennett@xxxxxxxxxxxxx> · Sun, 07 May 2006 22:28:31 -0700

Are there any instructions on this that are known to have worked 

successfully in the past for people who are reasonably good at following 

directions but don't know much about UNIX? :)

I lost over a month trying to get mod_perl installed because in every set 

of instructions that I found on the Web, every step -- no, I'm not 

exaggerating, *every step* in *every set of instructions* -- contained 

errors or omissions, and I had to post to a forum or write to my ISP 

practically very time.  There are too many examples to list, but the most 

straightforward one was: all the instructions pages said that mod_perl 1.x 

worked only with Apache 1.x and mod_perl 2.x worked only with Apache 2.x, 

so I lost a day hitting dead ends with 1.99x before finding out that 

mod_perl 1.99x is "counted as" a 2.x version.

I'd be surprised if the reason all those extra httpd processes were still 

running was because the clients didn't exit properly, because when running 

the stress test, "ab" reports on the number of successful and failed 

requests.  If all the requests are successful (and they almost always are), 

I'd assume that means the client got back a complete response from the 

server, after which the server can close the connection.

        -Bennett

At 12:07 AM 5/8/2006 -0500, Graham Frank wrote:

Eek!  Missed the second part of the post.

Webalizer is used to parse the logs.

Processes that don't exit might be stuck because the client didn't exit 

properly.

You might want to check out using the WORKER mpm.  It might handle Apache 

in a way better to your liking.

--Graham

-----Original Message-----

From:  Bennett Haselton <bennett@xxxxxxxxxxxxx>
Subj:  Re: [users@httpd] performance prob due to httpd's piling up
Date:  Sun May 7, 2006 11:55 pm
Size:  3K
To:  users@xxxxxxxxxxxxxxxx

Apache/2.0.52, CentOS 4, Dell Pentium 4 3.0 GHZ, 1 GB RAM.

Right now the output is:
 >>>
[root@server1 ~]# free -m

              total       used       free     shared    buffers 

cached

Mem:          1009        993         15          0          0         10
-/+ buffers/cache:        982         26
Swap:         2047       1672        374
 >>>

but I think that's because a process called webalizer is running which 

must

be what they use to parse the day's logs.

So is there a reason those extra instances of httpd keep hanging around in 

memory when there's nothing left for them to do, and would it increase
performance if I could make them go away?

         -Bennett

At 11:39 PM 5/7/2006 -0500, Graham Frank wrote:
>Hey,
>
>What OS?  What version of Apache?  Could you show us an output of "free
>-m"?.  What are the server specs?
>
>--Graham
>
>-----Original Message-----
>
>From:  Bennett Haselton <bennett@xxxxxxxxxxxxx>
>Subj:  [users@httpd] performance prob due to httpd's piling up
>Date:  Sun May 7, 2006 11:24 pm
>Size:  1K
>To:  users@xxxxxxxxxxxxxxxx
>
>I was running a stress test on a site that I run called
>StupidCensorship.com which frequently slows to a crawl due to high
>traffic.  From running a stress test on it using "ab" that sent 1,000
>concurrent requests to the site, I found that the number of running

>instances of /usr/sbin/httpd would rise from its initial default number 

of

>

>22, up to 258, and then stay steady at 258.  While the number was 

between

>22 and 258, the site performance was still OK, but once it hit 258, the
>response time was a lot slower.  I'm guessing this has something to do
>with
>the fact that while the number is climbing, the machine can just spawn a

>new instance of httpd to handle the request, but once it hits the 

maximum

>(due to hardware limits, I guess), new requests just get queued.
>

>Do these symptoms suggest any obvious way to improve performance, 

besides

>getting more RAM?  (And even more RAM would, I assume, only raise the
>limit
>of "httpd" instances that could run, but it would still plateau once it
>hit
>that limit.)
>
>One possibility: I noticed that even after the stress test was over, the

>number of running 'httpd' instances would fall very slowly, about one 

per

>second, until it got back down to 22.  I thought they were keeping the
>connection open, but my httpd.conf has KeepAlive set to Off.  If I could
>somehow get the httpd instances to just exit memory once they were done,
>instead of hanging around, would that solve the performance problem
>without
>any negative side effects?
>
>         -Bennett
>
>bennett@xxxxxxxxxxxxx     http://www.peacefire.org
>(425) 497 9002
>
>
>---------------------------------------------------------------------

>The official User-To-User support forum of the Apache HTTP Server 

Project.

>See <URL:http://httpd.apache.org/userslist.html> for more info.
>To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx
>    "   from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx
>For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
>
>
>
>
>
>---------------------------------------------------------------------

>The official User-To-User support forum of the Apache HTTP Server 

Project.

--- message truncated ---

---------------------------------------------------------------------
The official User-To-User support forum of the Apache HTTP Server Project.
See <URL:http://httpd.apache.org/userslist.html> for more info.
To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx
   "   from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx
For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx

---------------------------------------------------------------------
The official User-To-User support forum of the Apache HTTP Server Project.
See <URL:http://httpd.apache.org/userslist.html> for more info.
To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx
  "   from the digest: users-digest-unsubscribe@xxxxxxxxxxxxxxxx
For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx