Running a High-Performance Web Server on HPUX

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+ + +

+Date: Wed, 05 Nov 1997 16:59:34 -0800
+From: Rick Jones <raj@cup.hp.com>
+Reply-To: raj@cup.hp.com
+Organization: Network Performance
+Subject: HP-UX tuning tips
+

+ +

Here are some tuning tips for HP-UX to add to the tuning page.

+ +

For HP-UX 9.X: Upgrade to 10.20
+ For HP-UX 10.[00|01|10]: Upgrade to 10.20

+ +

For HP-UX 10.20:

+ +

Install the latest cumulative ARPA Transport Patch. This + will allow you to configure the size of the TCP connection + lookup hash table. The default is 256 buckets and must be set + to a power of two. This is accomplished with adb against the + *disc* image of the kernel. The variable name is tcp_hash_size. + Notice that it's critically important that you use "W" + to write a 32 bit quantity, not "w" to write a 16 bit + value when patching the disc image because the tcp_hash_size + variable is a 32 bit quantity.

+ +

How to pick the value? Examine the output of ftp://ftp.cup.hp.com/dist/networking/tools/connhist + and see how many total TCP connections exist on the system. You + probably want that number divided by the hash table size to be + reasonably small, say less than 10. Folks can look at HP's + SPECweb96 disclosures for some common settings. These can be + found at http://www.specbench.org/. + If an HP-UX system was performing at 1000 SPECweb96 connections + per second, the TIME_WAIT time of 60 seconds would mean + 60,000 TCP "connections" being tracked.

+ +

Folks can check their listen queue depths with ftp://ftp.cup.hp.com/dist/networking/misc/listenq.

+ +

If folks are running Apache on a PA-8000 based system, they + should consider "chatr'ing" the Apache executable to have a + large page size. This would be "chatr +pi L <BINARY>". + The GID of the running executable must have MLOCK privileges. + Setprivgrp(1m) should be consulted for assigning + MLOCK. The change can be validated by running Glance + and examining the memory regions of the server(s) to make sure that + they show a non-trivial fraction of the text segment being locked.

+ +

If folks are running Apache on MP systems, they might + consider writing a small program that uses mpctl() + to bind processes to processors. A simple pid % numcpu + algorithm is probably sufficient. This might even go into the + source code.

+ +

If folks are concerned about the number of FIN_WAIT_2 + connections, they can use nettune to shrink the value of + tcp_keepstart. However, they should be careful there - + certainly do not make it less than oh two to four minutes. If + tcp_hash_size has been set well, it is probably OK to + let the FIN_WAIT_2's take longer to timeout (perhaps + even the default two hours) - they will not on average have a big + impact on performance.

+ +

There are other things that could go into the code base, but + that might be left for another email. Feel free to drop me a + message if you or others are interested.

+ +

sincerely,

+ +

rick jones

+ +

http://www.cup.hp.com/netperf/NetperfPage.html

+ +