aspnet_wp.exe (100%) cpu leak

[Luk]

Hi,
we have got a problem with asp.net and we don't know what to do

Usually aspnet_wp.exe under medium/high load uses a maximum of 40% cpu
power.
Suddently even when requests are not so high it starts using 100% cpu.
Pages are so served in many seconds each (instead of few cents),
process threads and memory grows for all user new requests due to the
low speed or complete non working site. However we have not memory
problems (there is always enough free mem).
We can't understand what is using cpu and how to solve this problem.

It remains in this state for many minutes (sometimes hours...) if we
don't kill aspnet_wp.exe before. Even after process restarts aspnet
compile aspx files and in this moment the cpu is normally high for few
seconds.Then the cpu is on normal values also with many requests.
This problem returns sometimes after hours, often after few minutes.

In machine.config:

<processModel
enable="true"
timeout="Infinite"
idleTimeout="Infinite"
shutdownTimeout="0:00:05"
requestLimit="Infinite"
requestQueueLimit="600"
restartQueueLimit="10"
memoryLimit="60"
webGarden="false"
cpuMask="0xffffffff"
userName="machine"
password="AutoGenerate"
logLevel="Errors"
clientConnectedCheck="0:00:05"
comAuthenticationLevel="Connect"
comImpersonationLevel="Impersonate"
responseDeadlockInterval="00:03:00"
maxWorkerThreads="20"
maxIoThreads="20"
/>

But we tried many configuration here with no useful results:
maxWorkerThreads and maxIoThreads from 13 to 100, and
requestQueueLimit from 300 to 5000. aspnet_wp.exe goes to 100% when it
wants and goes down only after several minutes (this could be more

We monitored some info in performance counters but didn't find
anything useful.

We don't use monitors, software lock, or critical section in the code.
We store a lot of data at application level (using global.asax), and
some in session state (with cookie, inProc).
All exception we can handle are saved, and there is nothing strange.

Help us please... Thanks

Server is:
- dual Xeon 2.8 GHz (with HT active), 2GB RAM,
- Win2k server SP3 (and other patchs...) + IIS 5
- .NET Framework v1.1.4322
- isapi filter used : flatcompression (www.flatcompression.org) and
urlscan
- MySQL driver used: MyOdbc-3.51.06 and MySQLDriverCS-3.0.13

 

[Alvin Bruney [MVP]]

have you changed or updated the running code recently? to fix a bug or
something? I'm thinking this is buggy code introduced into the system

what do your application event logs say?

 

[F. L.]

Thank you for your reply

I have always had this problem. But once it happened 1 time a week. Now
it's much more frequent, and in the last weeks even several times a
day...

There's nothing on the application event log, process don't recycle on
his own (i have to kill it, or wait a lot...)

Code changes frequently for new services or improvements. I tried to
isolate and modify some features that could have been heavy to manage
(that used monitor to access to a global resource, now with an external
mysql heap table).
I still store a lot of data in global objects (some hashtables taking
about 700 mb on high load), but i dont think this is a problem.

What could i monitor in performance counter to understand what is using
cpu?
I noticed that both GC counters and exceptions/s reports same values in
both cpu situations.
I dont know if it's a code loop or a performance issue connected to a
bug, or something else...

thanks

Re: aspnet_wp.exe (100%) cpu leak
From: Alvin Bruney [MVP]

have you changed or updated the running code recently? to
fix a bug or
something? I'm thinking this is buggy code introduced into
the system

 

[Alvin Bruney [MVP]]

Are you pumped? Roll up your sleeves because this will make you sweat, more
like cry out for mamma. (it's a lot of work basically)

start here
http://www.microsoft.com/technet/pr...chnologies/iis/support/trblshoot/tshicpu.mspx