From Martin.Kraemer@mch.sni.de Fri Apr 17 15:03:08 1998 Date: Thu, 13 Nov 1997 15:04:24 +0100 From: Martin Kraemer To: new-httpd@apache.org Subject: Re: Minimizing number of system calls? Reply-To: new-httpd@apache.org On Wed, Nov 12, 1997 at 09:47:40PM -0800, Dean Gaudet wrote: > I actually thought of another call I could remove, but the trick to do it > is escaping me right now ... I'll update the document next time it comes > back to me. I observed a number of redundant system calls on various SVR4 systems: depending on the setting of the TZ environment variable, _each_ call to gettimeofday() could cost three extra system calls: open("/usr/lib/locale/TZ/localtime", O_RDONLY, 0) = 3 read(3, "\0\0\0\0\0\0\0\0\0\0\0\0".., 7944) = 778 close(3) = 0 This happens only if the TZ variable uses the external time zone files (when you set TZ=:{timezone}, e.g., TZ=:MET), not when the SYSV syntax with the summer time algorithm included in the TZ setting is used (e.g., TZ="MET-1MDT,M3.5.0/02:00:00,M10.5.0/03:00:00"). I think we should warn users _somewhere_ that SVR4 performance can be slightly improved by setting the TZ variable right :-( Martin -- | S I E M E N S | | Siemens Nixdorf | ------------- | Voice: +49-89-636-46021 | Informationssysteme AG | N I X D O R F | FAX: +49-89-636-44994 | 81730 Munich, Germany ~~~~~~~~~~~~~~~~My opinions only, of course; pgp key available on request