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diff --git a/APACHE_1_3_42/htdocs/manual/misc/perf-dec.html b/APACHE_1_3_42/htdocs/manual/misc/perf-dec.html new file mode 100644 index 0000000000..611bed6884 --- /dev/null +++ b/APACHE_1_3_42/htdocs/manual/misc/perf-dec.html @@ -0,0 +1,287 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml"> + <head> + <meta name="generator" content="HTML Tidy, see www.w3.org" /> + + <title>Performance Tuning Tips for Digital Unix</title> + </head> + <!-- Background white, links blue (unvisited), navy (visited), red (active) --> + + <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" + vlink="#000080" alink="#FF0000"> + <!--#include virtual="header.html" --> + + <h1 align="CENTER">Performance Tuning Tips for Digital + Unix</h1> + Below is a set of newsgroup posts made by an engineer from DEC + in response to queries about how to modify DEC's Digital Unix + OS for more heavily loaded web sites. Copied with permission. + <hr /> + + <h2>Update</h2> + From: Jeffrey Mogul <mogul@pa.dec.com><br /> + Date: Fri, 28 Jun 96 16:07:56 MDT<br /> + + + <ol> + <li>The advice given in the README file regarding the + "tcbhashsize" variable is incorrect. The largest value this + should be set to is 1024. Setting it any higher will have the + perverse result of disabling the hashing mechanism.</li> + + <li> + Patch ID OSF350-146 has been superseded by + + <blockquote> + Patch ID OSF350-195 for V3.2C<br /> + Patch ID OSF360-350195 for V3.2D + </blockquote> + Patch IDs for V3.2E and V3.2F should be available soon. + There is no known reason why the Patch ID OSF360-350195 + won't work on these releases, but such use is not + officially supported by Digital. This patch kit will not be + needed for V3.2G when it is released. + </li> + </ol> + <hr /> +<pre> +From mogul@pa.dec.com (Jeffrey Mogul) +Organization DEC Western Research +Date 30 May 1996 00:50:25 GMT +Newsgroups <a +href="news:comp.unix.osf.osf1">comp.unix.osf.osf1</a> +Message-ID <4oirch$bc8@usenet.pa.dec.com> +Subject Re: Web Site Performance +References 1 + + + +In article <skoogDs54BH.9pF@netcom.com> skoog@netcom.com (Jim Skoog) writes: +>Where are the performance bottlenecks for Alpha AXP running the +>Netscape Commerce Server 1.12 with high volume internet traffic? +>We are evaluating network performance for a variety of Alpha AXP +>runing DEC UNIX 3.2C, which run DEC's seal firewall and behind +>that Alpha 1000 and 2100 webservers. + +Our experience (running such Web servers as <a +href="http://altavista.digital.com">altavista.digital.com</a> +and <a +href="http://www.digital.com">www.digital.com</a>) is that there is one important kernel tuning +knob to adjust in order to get good performance on V3.2C. You +need to patch the kernel global variable "somaxconn" (use dbx -k +to do this) from its default value of 8 to something much larger. + +How much larger? Well, no larger than 32767 (decimal). And +probably no less than about 2048, if you have a really high volume +(millions of hits per day), like AltaVista does. + +This change allows the system to maintain more than 8 TCP +connections in the SYN_RCVD state for the HTTP server. (You +can use "netstat -An |grep SYN_RCVD" to see how many such +connections exist at any given instant). + +If you don't make this change, you might find that as the load gets +high, some connection attempts take a very long time. And if a lot +of your clients disconnect from the Internet during the process of +TCP connection establishment (this happens a lot with dialup +users), these "embryonic" connections might tie up your somaxconn +quota of SYN_RCVD-state connections. Until the kernel times out +these embryonic connections, no other connections will be accepted, +and it will appear as if the server has died. + +The default value for somaxconn in Digital UNIX V4.0 will be quite +a bit larger than it has been in previous versions (we inherited +this default from 4.3BSD). + +Digital UNIX V4.0 includes some other performance-related changes +that significantly improve its maximum HTTP connection rate. However, +we've been using V3.2C systems to front-end for altavista.digital.com +with no obvious performance bottlenecks at the millions-of-hits-per-day +level. + +We have some Webstone performance results available at + http://www.digital.com/info/alphaserver/news/webff.html + +<em>[The document referenced above is no longer at that URL -- Ed.]</em> + +I'm not sure if these were done using V4.0 or an earlier version +of Digital UNIX, although I suspect they were done using a test +version of V4.0. + +-Jeff + +---------------------------------------------------------------------------- + +From mogul@pa.dec.com (Jeffrey Mogul) +Organization DEC Western Research +Date 31 May 1996 21:01:01 GMT +Newsgroups <a +href="news:comp.unix.osf.osf1">comp.unix.osf.osf1</a> +Message-ID <4onmmd$mmd@usenet.pa.dec.com> +Subject Digital UNIX V3.2C Internet tuning patch info + +---------------------------------------------------------------------------- + +Something that probably few people are aware of is that Digital +has a patch kit available for Digital UNIX V3.2C that may improve +Internet performance, especially for busy web servers. + +This patch kit is one way to increase the value of somaxconn, +which I discussed in a message here a day or two ago. + +I've included in this message the revised README file for this +patch kit below. Note that the original README file in the patch +kit itself may be an earlier version; I'm told that the version +below is the right one. + +Sorry, this patch kit is NOT available for other versions of Digital +UNIX. Most (but not quite all) of these changes also made it into V4.0, +so the description of the various tuning parameters in this README +file might be useful to people running V4.0 systems. + +This patch kit does not appear to be available (yet?) from + <a +href="http://www.service.digital.com/html/patch_service.html">http://www.service.digital.com/html/patch_service.html</a> +so I guess you'll have to call Digital's Customer Support to get it. + +-Jeff + +DESCRIPTION: Digital UNIX Network tuning patch + + Patch ID: OSF350-146 + + SUPERSEDED PATCHES: OSF350-151, OSF350-158 + + This set of files improves the performance of the network + subsystem on a system being used as a web server. There are + additional tunable parameters included here, to be used + cautiously by an informed system administrator. + +TUNING + + To tune the web server, the number of simultaneous socket + connection requests are limited by: + + somaxconn Sets the maximum number of pending requests + allowed to wait on a listening socket. The + default value in Digital UNIX V3.2 is 8. + This patch kit increases the default to 1024, + which matches the value in Digital UNIX V4.0. + + sominconn Sets the minimum number of pending connections + allowed on a listening socket. When a user + process calls listen with a backlog less + than sominconn, the backlog will be set to + sominconn. sominconn overrides somaxconn. + The default value is 1. + + The effectiveness of tuning these parameters can be monitored by + the sobacklog variables available in the kernel: + + sobacklog_hiwat Tracks the maximum pending requests to any + socket. The initial value is 0. + + sobacklog_drops Tracks the number of drops exceeding the + socket set backlog limit. The initial + value is 0. + + somaxconn_drops Tracks the number of drops exceeding the + somaxconn limit. When sominconn is larger + than somaxconn, tracks the number of drops + exceeding sominconn. The initial value is 0. + + TCP timer parameters also affect performance. Tuning the following + require some knowledge of the characteristics of the network. + + tcp_msl Sets the tcp maximum segment lifetime. + This is the maximum lifetime in half + seconds that a packet can be in transit + on the network. This value, when doubled, + is the length of time a connection remains + in the TIME_WAIT state after a incoming + close request is processed. The unit is + specified in 1/2 seconds, the initial + value is 60. + + tcp_rexmit_interval_min + Sets the minimum TCP retransmit interval. + For some WAN networks the default value may + be too short, causing unnecessary duplicate + packets to be sent. The unit is specified + in 1/2 seconds, the initial value is 1. + + tcp_keepinit This is the amount of time a partially + established connection will sit on the listen + queue before timing out (<em>e.g.</em>, if a client + sends a SYN but never answers our SYN/ACK). + Partially established connections tie up slots + on the listen queue. If the queue starts to + fill with connections in SYN_RCVD state, + tcp_keepinit can be decreased to make those + partial connects time out sooner. This should + be used with caution, since there might be + legitimate clients that are taking a while + to respond to SYN/ACK. The unit is specified + in 1/2 seconds, the default value is 150 + (ie. 75 seconds). + + The hashlist size for the TCP inpcb lookup table is regulated by: + + tcbhashsize The number of hash buckets used for the + TCP connection table used in the kernel. + The initial value is 32. For best results, + should be specified as a power of 2. For + busy Web servers, set this to 2048 or more. + + The hashlist size for the interface alias table is regulated by: + + inifaddr_hsize The number of hash buckets used for the + interface alias table used in the kernel. + The initial value is 32. For best results, + should be specified as a power of 2. + + ipport_userreserved The maximum number of concurrent non-reserved, + dynamically allocated ports. Default range + is 1025-5000. The maximum value is 65535. + This limits the numer of times you can + simultaneously telnet or ftp out to connect + to other systems. + + tcpnodelack Don't delay acknowledging TCP data; this + can sometimes improve performance of locally + run CAD packages. Default is value is 0, + the enabled value is 1. + + Digital UNIX version: + + V3.2C +Feature V3.2C patch V4.0 +======= ===== ===== ==== +somaxconn X X X +sominconn - X X +sobacklog_hiwat - X - +sobacklog_drops - X - +somaxconn_drops - X - +tcpnodelack X X X +tcp_keepidle X X X +tcp_keepintvl X X X +tcp_keepcnt - X X +tcp_keepinit - X X +TCP keepalive per-socket - - X +tcp_msl - X - +tcp_rexmit_interval_min - X - +TCP inpcb hashing - X X +tcbhashsize - X X +interface alias hashing - X X +inifaddr_hsize - X X +ipport_userreserved - X - +sysconfig -q inet - - X +sysconfig -q socket - - X + +</pre> + <!--#include virtual="footer.html" --> + </body> +</html> + |