Date: Thu, 30 Aug 2001 13:48:32 +0200 (CEST) From: Martin Blapp <mb@imp.ch> To: <bkarp@icsi.berkeley.edu>, <kpielorz@tdx.co.uk>, <sthaug@nethelp.no>, <atrn@zeta.org.au>, <roberto@eurocontrol.fr>, <drussell@saturn-tech.com> Cc: <phk@freebsd.org>, <Patrick.Guelat@imp.ch>, <freebsd-hackers@freebsd.org>, <freebsd-smp@freebsd.org> Subject: Clock speedup on 4.X FreeBSD SMP and serverworks chipset Message-ID: <20010830133205.N676-100000@levais.imp.ch> In-Reply-To: <20010830122354.A42964@caerdonn.eurocontrol.fr>
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Hi,
Searching the freebsd mailinglists I have seen that you also suffering
under this problem on 4.X. STABLE:
I have isolated the problem to be due reading the time with microtime()
Execute this programm:
#include <sys/types.h>
#include <sys/time.h>
#include <err.h>
int
main(void)
{
for(;;) {
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
}
return (0);
}
and you will see a 10% timedrift. For 20 seconds, I get 2 second
time speedup.
You should not see this time drift if you remove the gettimeofday()
syscall of the programm.
If someone has a machine where he can install CURRENT, or has a machine
with ServerWorks Chipset and SMP, is it possible that he can activate
ACPI and test it again ?
There is already a PR, PR kern/30135.
Martin
Martin Blapp, mb@imp.ch
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