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Posted to bugs@httpd.apache.org by bu...@apache.org on 2011/12/27 20:07:14 UTC

DO NOT REPLY [Bug 52391] New: 100% CPU usage while using Forward Proxy

https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

             Bug #: 52391
           Summary: 100% CPU usage while using Forward Proxy
           Product: Apache httpd-2
           Version: 2.2.21
          Platform: PC
            Status: NEW
          Severity: critical
          Priority: P2
         Component: All
        AssignedTo: bugs@httpd.apache.org
        ReportedBy: sam.vanbrussel@linqed.be
    Classification: Unclassified


Dear,

At a certain point in time, httpd.exe starts using 100% cpu (one thread, so
12,5% on my 8-core machine). Over time, this shifts to 25%, 37,5%, 50% and
higher, so I restart the service. I started noticing it since version 2.2.17.

The configuration file httpd.conf is the standard one with the following
additions:

#Begin custom modules SVB

LoadModule cache_module modules/mod_cache.so
LoadModule disk_cache_module modules/mod_disk_cache.so

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_scgi_module modules/mod_proxy_scgi.so

#End custom modules SVB

#Begin custom settings SVB

<IfModule mod_cache.c>
    <IfModule mod_disk_cache.c>
        CacheDirLength 1
        CacheDirLevels 2
        CacheMaxFileSize 1000000000
        CacheMinFileSize 1
        CacheRoot T:\Apache\HTTPD\CacheRoot
        CacheEnable disk /
    </IfModule>
</IfModule>

ProxyRequests On
ProxyVia On

<Proxy *>
    Order deny,allow
    Deny from all
    Allow from 192.168.1
</Proxy>

#End custom settings SVB

Can I help you by adding a memory dump file and some log files?

Kind regards,

Sam

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DO NOT REPLY [Bug 52391] 100% CPU usage while using Forward Proxy

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

Sascha Kuehndel <sa...@deka.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sascha.kuehndel@deka.de

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DO NOT REPLY [Bug 52391] 100% CPU usage while using Forward Proxy

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

William A. Rowe Jr. <wr...@apache.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         OS/Version|                            |All

--- Comment #1 from William A. Rowe Jr. <wr...@apache.org> 2011-12-27 22:55:58 UTC ---
First, begin by setting both EnableSendfile / EnableMMAP off - and then also
try DisableWin32AcceptEx.

It's important to eliminate these optimizations to be sure it doesn't have
something to do with your network driver stack.

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DO NOT REPLY [Bug 52391] 100% CPU usage while using Forward Proxy

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

lingpeng <li...@hotmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |52870

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DO NOT REPLY [Bug 52391] 100% CPU usage while using Forward Proxy

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

--- Comment #3 from Sam Van Brussel <sa...@linqed.be> 2011-12-30 08:57:02 UTC ---
The issue seems to occur a lot less. Before your fix, it was pretty easy to get
load on the httpd.exe process and even move to 100% CPU (one idle httpd.exe and
one httpd.exe that moves all cores to 100%). After your fix, I've only got a
single spike to 12,5%.

I even noted something interesting: as soon as I closed my browser, httpd.exe
went completely idle.

I use Firefox and enable the pipeline settings (I'm doing that for years).

network.http.pipelining;true
network.http.pipelining.maxrequests;8
network.http.pipelining.ssl;true
network.http.proxy.pipelining;true

Could it be that Firefox overloads Apache?

Kind regards,

Sam

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DO NOT REPLY [Bug 52391] 100% CPU usage while using Forward Proxy

Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=52391

--- Comment #2 from Sam Van Brussel <sa...@linqed.be> 2011-12-29 23:10:48 UTC ---
Dear,

I've uncommented the EnableMMAP and EnableSendfile lines in the httpd.conf file

#
# EnableMMAP and EnableSendfile: On systems that support it, 
# memory-mapping or the sendfile syscall is used to deliver
# files.  This usually improves server performance, but must
# be turned off when serving from networked-mounted 
# filesystems or if support for these functions is otherwise
# broken on your system.
#
EnableMMAP off
EnableSendfile off

I'll re-evaluate the new configuration. I couldn't find much documentation
about the DisableWin32AcceptEx and haven't applied it yet.

Kind regards,

Sam

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