From: Pavel Machek <pavel@suse.cz>
To: Andrea Arcangeli <andrea@suse.de>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>,
Con Kolivas <kernel@kolivas.org>,
linux-kernel@vger.kernel.org
Subject: Time goes crazy in 2.6.9 after long cli [was Re: USB making time drift]
Date: Thu, 16 Dec 2004 02:15:49 +0100 [thread overview]
Message-ID: <20041216011549.GD6285@elf.ucw.cz> (raw)
In-Reply-To: <20041214220239.GA19221@elf.ucw.cz>
Hi!
> > > Are you using CONFIG_HPET_TIMER by chance? It seems to be missing some
> > > strategic -1, TSC (etc) get it right.
> >
> > I'm not using hpet because it's an old hardware, this is with timer_tsc.
> > It must be reproducible in any machine out there, especially with
> > machines with usb it should be reproducible even without any userspace
> > testcase doing iopl/cli/sti. Time will go silenty in the future at every
> > usb irq (they often last 3/4msec).
>
> How much drift do you see?
>
> I have machine with UHCI here, and am using usb most of the time
> (bluetooth for gprs connection), and did not notice too bad
> drift. ntpdate does some adjustment each time I connect to the
> network, but it
Okay, I have good news and bad news. Bad news is that it is broken on
my machine, too. Good news is that breakage is not at all subtle.
root@amd:/home/pavel/misc# time ./latency
0.00user 0.00system 1.69 (0m1.694s) elapsed 0.17%CPU
root@amd:/home/pavel/misc# time ./latency
0.00user 0.00system 4293.47 (71m33.478s) elapsed 0.00%CPU
root@amd:/home/pavel/misc#
71 minutes when it ran for 2.5 seconds?!
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:04:24 ntpdate[6385]: adjust time server 195.113.144.238
offset 0.010865 sec
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:08:07 ntpdate[6405]: step time server 195.113.144.238 offset
85.903997 sec
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:09:02 ntpdate[6410]: step time server 195.113.144.238 offset
4.306853 sec
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:09:11 ntpdate[6411]: adjust time server 195.113.144.238
offset -0.028829 sec
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:09:27 ntpdate[6413]: step time server 195.113.144.238 offset
4.283117 sec
root@amd:~# ntpdate tak.cesnet.cz
16 Dec 02:09:47 ntpdate[6415]: step time server 195.113.144.238 offset
4.286300 sec
root@amd:~#
It seems that each cycle of attached program (needs root) breaks
system time by 4 seconds... I do not know why it printed 71minutes
there. That seems like some underflow somewhere.. Strange, now it
happened again.
void
main(void)
{
int i;
iopl(3);
while (1) {
asm volatile("cli");
// for (i=0; i<20000000; i++)
for (i=0; i<1000000000; i++)
asm volatile("");
asm volatile("sti");
sleep(1);
}
}
Actually it seems to create some sort havoc in timer
subsystem... Actually it is reproducible:
root@amd:/home/pavel/misc# date; time ./latency ; date; sleep 1; date; sleep 1; date; sleep 1; date
Thu Dec 16 02:14:18 CET 2004
0.00user 0.00system 4293.51 (71m33.516s) elapsed 0.00%CPU
Thu Dec 16 03:25:51 CET 2004
Thu Dec 16 02:14:18 CET 2004
Thu Dec 16 02:14:19 CET 2004
Thu Dec 16 02:14:20 CET 2004
root@amd:/home/pavel/misc# date; time ./latency ; date; sleep 1; date; sleep 1; date; sleep 1; date
Thu Dec 16 02:14:23 CET 2004
0.00user 0.00system 4293.52 (71m33.521s) elapsed 0.00%CPU
Thu Dec 16 03:25:56 CET 2004
Thu Dec 16 03:25:57 CET 2004
Thu Dec 16 02:14:23 CET 2004
Thu Dec 16 02:14:24 CET 2004
root@amd:/home/pavel/misc#
Pavel
--
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!
next prev parent reply other threads:[~2004-12-16 1:58 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-11 14:23 dynamic-hz Andrea Arcangeli
2004-12-11 14:50 ` dynamic-hz Zwane Mwaikambo
2004-12-12 6:57 ` dynamic-hz Andrea Arcangeli
2004-12-11 21:41 ` dynamic-hz Jan Engelhardt
2004-12-12 16:35 ` dynamic-hz Pavel Machek
2004-12-12 22:23 ` dynamic-hz Andrea Arcangeli
2004-12-12 23:36 ` dynamic-hz Con Kolivas
2004-12-12 23:42 ` dynamic-hz Pavel Machek
2004-12-13 0:09 ` dynamic-hz Con Kolivas
2004-12-13 8:37 ` dynamic-hz Jan Engelhardt
2004-12-13 10:43 ` dynamic-hz Pavel Machek
2004-12-13 11:08 ` dynamic-hz Andrea Arcangeli
2004-12-13 19:36 ` dynamic-hz john stultz
2004-12-12 23:43 ` dynamic-hz Andrea Arcangeli
2004-12-13 0:18 ` dynamic-hz Con Kolivas
2004-12-13 0:27 ` dynamic-hz Andrea Arcangeli
2004-12-13 1:50 ` dynamic-hz Zwane Mwaikambo
2004-12-13 11:28 ` dynamic-hz Andrea Arcangeli
2004-12-13 12:43 ` dynamic-hz Pavel Machek
2004-12-13 12:58 ` dynamic-hz Andrea Arcangeli
2004-12-13 19:12 ` dynamic-hz Pavel Machek
2004-12-13 20:34 ` dynamic-hz john stultz
2004-12-13 20:49 ` dynamic-hz Pavel Machek
2004-12-14 2:04 ` dynamic-hz Andrea Arcangeli
[not found] ` <20041214013924.GB14617@atomide.com>
2004-12-14 9:37 ` dynamic-hz Pavel Machek
2004-12-14 21:18 ` dynamic-hz Tony Lindgren
2004-12-14 22:06 ` dynamic-hz Pavel Machek
2004-12-14 23:00 ` dynamic-hz linux-os
2004-12-14 23:13 ` dynamic-hz Tony Lindgren
2004-12-22 20:02 ` dynamic-hz Tony Lindgren
2004-12-14 23:04 ` dynamic-hz Tony Lindgren
2004-12-14 2:46 ` dynamic-hz Andrea Arcangeli
2004-12-14 19:24 ` dynamic-hz john stultz
2004-12-14 2:36 ` dynamic-hz Andrea Arcangeli
2004-12-14 9:39 ` dynamic-hz Pavel Machek
2004-12-14 9:59 ` dynamic-hz Pavel Machek
2004-12-14 15:25 ` dynamic-hz Andrea Arcangeli
2004-12-14 22:02 ` USB making time drift [was Re: dynamic-hz] Pavel Machek
2004-12-14 23:16 ` Andrea Arcangeli
2004-12-15 2:59 ` Gene Heskett
2004-12-15 9:17 ` Andrea Arcangeli
2004-12-15 16:44 ` Gene Heskett
2004-12-15 18:20 ` Andrea Arcangeli
2004-12-16 1:59 ` Gene Heskett
2004-12-16 11:30 ` Andrea Arcangeli
2004-12-16 12:50 ` Alan Cox
2004-12-15 20:16 ` Pavel Machek
2004-12-16 2:02 ` Gene Heskett
2004-12-15 17:03 ` Gene Heskett
2004-12-15 17:48 ` Tim Schmielau
2004-12-16 2:03 ` Gene Heskett
2004-12-16 0:58 ` Pavel Machek
2004-12-16 2:33 ` john stultz
2004-12-16 1:15 ` Pavel Machek [this message]
2004-12-16 11:13 ` Time goes crazy in 2.6.9 after long cli [was Re: USB making time drift] Andrea Arcangeli
2004-12-16 12:49 ` Alan Cox
2004-12-13 14:50 ` dynamic-hz Zwane Mwaikambo
2004-12-13 7:43 ` dynamic-hz Stefan Seyfried
2004-12-13 13:58 ` dynamic-hz Russell King
2004-12-13 14:14 ` dynamic-hz Russell King
2004-12-13 14:52 ` dynamic-hz Alan Cox
2004-12-13 16:23 ` dynamic-hz Russell King
2004-12-13 17:53 ` dynamic-hz Michael Buesch
2004-12-13 18:04 ` dynamic-hz Russell King
2004-12-13 19:04 ` dynamic-hz Pavel Machek
2004-12-13 20:11 ` dynamic-hz Russell King
2004-12-14 0:16 ` dynamic-hz Eric St-Laurent
2004-12-15 18:04 ` dynamic-hz Alan Cox
2004-12-15 19:54 ` dynamic-hz linux-os
2004-12-16 2:17 ` dynamic-hz Gene Heskett
2004-12-16 12:42 ` dynamic-hz linux-os
2004-12-17 20:12 ` dynamic-hz H. Peter Anvin
2004-12-16 9:10 ` dynamic-hz Gabriel Paubert
2004-12-16 12:17 ` dynamic-hz Geert Uytterhoeven
2004-12-16 14:00 ` dynamic-hz Mitchell Blank Jr
2004-12-13 15:30 ` dynamic-hz Zwane Mwaikambo
2004-12-13 15:59 ` dynamic-hz Russell King
2004-12-13 16:14 ` dynamic-hz Pavel Machek
2004-12-13 16:06 ` dynamic-hz Pavel Machek
2004-12-13 16:19 ` dynamic-hz Jan Engelhardt
2004-12-13 8:29 ` dynamic-hz Jan Engelhardt
2004-12-14 22:54 ` dynamic-hz Lee Revell
2004-12-14 23:38 ` dynamic-hz Chris Friesen
2004-12-15 8:32 ` dynamic-hz Jan Engelhardt
2004-12-13 11:02 ` dynamic-hz Andrew Morton
2004-12-13 11:17 ` dynamic-hz Andrea Arcangeli
2004-12-13 11:25 ` dynamic-hz Andrew Morton
2004-12-13 11:47 ` dynamic-hz Andrea Arcangeli
2004-12-14 3:56 ` dynamic-hz Nish Aravamudan
2004-12-14 3:54 ` dynamic-hz Nish Aravamudan
2004-12-14 4:29 ` dynamic-hz Andrew Morton
2004-12-14 5:25 ` dynamic-hz Nish Aravamudan
2004-12-17 20:10 ` dynamic-hz Nish Aravamudan
2004-12-14 10:01 ` dynamic-hz Domen Puncer
2004-12-14 16:56 ` dynamic-hz Nish Aravamudan
2004-12-14 14:23 ` dynamic-hz linux-os
2004-12-14 16:54 ` dynamic-hz Nish Aravamudan
2004-12-14 17:15 ` dynamic-hz Andrea Arcangeli
2004-12-14 17:42 ` dynamic-hz Nish Aravamudan
2004-12-14 18:29 ` dynamic-hz Andrea Arcangeli
2004-12-14 19:00 ` dynamic-hz Nish Aravamudan
2004-12-14 18:22 ` dynamic-hz linux-os
2004-12-14 18:38 ` dynamic-hz Andrea Arcangeli
2004-12-14 18:50 ` dynamic-hz Pavel Machek
2004-12-13 11:19 ` dynamic-hz Hans Kristian Rosbach
2004-12-13 11:22 ` dynamic-hz Pavel Machek
2004-12-13 11:39 ` dynamic-hz Andrea Arcangeli
2004-12-13 12:51 ` dynamic-hz Hans Kristian Rosbach
2004-12-13 13:01 ` dynamic-hz Andrea Arcangeli
2004-12-13 13:02 ` dynamic-hz Andrea Arcangeli
2004-12-13 15:06 ` dynamic-hz Geert Uytterhoeven
2004-12-13 16:12 ` dynamic-hz Pavel Machek
2004-12-13 16:14 ` dynamic-hz Geert Uytterhoeven
2004-12-14 4:06 ` dynamic-hz Nish Aravamudan
2004-12-14 4:05 ` dynamic-hz Nish Aravamudan
2004-12-13 11:33 ` dynamic-hz Andrea Arcangeli
2004-12-13 14:38 ` dynamic-hz Zwane Mwaikambo
2004-12-13 12:00 ` dynamic-hz Alan Cox
2004-12-13 15:52 ` dynamic-hz Andrea Arcangeli
2004-12-14 22:28 ` dynamic-hz Lee Revell
2004-12-14 22:40 ` dynamic-hz Con Kolivas
2004-12-14 22:50 ` dynamic-hz Lee Revell
2004-12-13 20:26 ` dynamic-hz Olaf Hering
2004-12-13 22:41 ` dynamic-hz Andrea Arcangeli
2004-12-13 20:56 ` dynamic-hz john stultz
2004-12-13 22:21 ` dynamic-hz Andrea Arcangeli
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