ASP.net Threadpool Optimizations for the 1.1 Machine.config

If you’re using ASP.net 1.1 and your web server has more than one processor it is probably advisable to consider testing some "threadpool optimizations." These optimizations are not guaranteed to be perfect for your environment but generally they are very good recommendations. I’d recommend testing with them and, if desired, tweaking them to your own specifications as you see fit.

The default settings in the C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\CONFIG\machine.config file are:

maxconnection 2;

maxIoThreads 20;

maxWorkerThreads 20;

minFreeThreads 8;

minLocalRequestFreeThreads 4

Consider beginning optimization attempts using the following formula:

maxconnection 12 * #CPUs ;

maxIoThreads 100;

maxWorkerThreads 100;

minFreeThreads 88 * #CPUs;

minLocalRequestFreeThreads 76 * #CPUs

minWorkerThreads 50 [this one needs to be added]

You might want to doublecheck my math on this cheat-sheet before using them:

Two Processors:	Four Processors:	Eight Processors:	Twelve Processors:
maxconnection="24"	maxconnection="48"	maxConnection=”96”	maxConnection=”144”
minFreeThreads="176"	minFreeThreads="352"	minFreeThreads="704"	minFreeThreads="1056"
minLocalRequestFreeThreads="152"	minLocalRequestFreeThreads="304"	minLocalRequestFreeThreads="608"	minLocalRequestFreeThreads="912"
maxWorkerThreads="100"	maxWorkerThreads="100"	maxWorkerThreads="100"	maxWorkerThreads="100"
minWorkerThreads="50"	minWorkerThreads="50"	minWorkerThreads="50"	minWorkerThreads="50"
maxIoThreads="100"	maxIoThreads="100"	maxIoThreads="100"	maxIoThreads="100"

As an example, on a four processor web server, the machine.config settings highlighted in yellow (ignore the ones that are not highlighted please) need to be changed to something resembling the following:

<connectionManagement>

<add address="*"

maxconnection="48"

/>

 <httpRuntime

executionTimeout="90"

maxRequestLength="4096"

useFullyQualifiedRedirectUrl="false"

minFreeThreads="352"

minLocalRequestFreeThreads="304"

appRequestQueueLimit="100"

enableVersionHeader="true"

/>

<processModel

enable="true"

timeout="Infinite"

idleTimeout="Infinite"

shutdownTimeout="0:00:05"

requestLimit="Infinite"

requestQueueLimit="5000"

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="100"

minWorkerThreads="50"

maxIoThreads="100"

/>

After making these improvements, be sure to restart IIS with an IISRESET and test your ASP.net pages.  

These optimizations are not needed with ASP.net 2.0 since the machine.config file has autoconfig set to true by default.

 Reference:

KB 821268 Contention, poor performance, and deadlocks when you make Web service requests from ASP.NET applications

http://support.microsoft.com/default.aspx?scid=kb;EN-US;821268