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From: Pavel Machek <pavel@suse.cz>
To: Tony Lindgren <tony@atomide.com>
Cc: George Anzinger <george@mvista.com>,
	john stultz <johnstul@us.ibm.com>,
	Andrea Arcangeli <andrea@suse.de>,
	Zwane Mwaikambo <zwane@arm.linux.org.uk>,
	Con Kolivas <kernel@kolivas.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dynamic tick patch
Date: Wed, 19 Jan 2005 23:06:37 +0100	[thread overview]
Message-ID: <20050119220637.GA7513@elf.ucw.cz> (raw)
In-Reply-To: <20050119171106.GA14545@atomide.com>

Hi!

> > > As this patch is related to the VST/High-Res timers, there
> > > are probably various things that can be merged. I have not
> > > yet looked at what all could be merged.
> > > 
> > > I'd appreciate some comments and testing!
> > 
> > Good news is that it does seem to reduce number of interrupts. Bad
> > news is that time now runs faster (like "sleep 10" finishes in ~5
> > seconds) and that I could not measure any difference in power
> > consumption.
> 
> Thanks for trying it out. I have quite accurate time here on my
> systems, and sleep works as it should. I wonder what's happening on
> your system? If you have a chance, could you please post the results
> from following simple tests?

Unpatched 2.6.11-rc1:

root@amd:~# dmesg | grep -i time; for i in 1 2 3 4 5; do ntpdate -b tak.cesnet.cz && sleep 10; done ; date && sleep 10 && date; while [ 1 ]; do date; done | uniq
PCI: Setting latency timer of device 0000:00:11.5 to 64
19 Jan 22:53:20 ntpdate[7943]: step time server 195.113.144.238 offset 0.013070 sec
19 Jan 22:53:36 ntpdate[8169]: step time server 195.113.144.238 offset -0.005736 sec
19 Jan 22:53:51 ntpdate[8427]: step time server 195.113.144.238 offset -0.010292 sec
19 Jan 22:54:06 ntpdate[8647]: step time server 195.113.144.238 offset -0.045055 sec
19 Jan 22:54:21 ntpdate[8889]: step time server 195.113.144.238 offset 0.054865 sec
Wed Jan 19 22:54:31 CET 2005
Wed Jan 19 22:54:41 CET 2005
Wed Jan 19 22:54:41 CET 2005
Wed Jan 19 22:54:42 CET 2005
Wed Jan 19 22:54:43 CET 2005
Wed Jan 19 22:54:44 CET 2005
Wed Jan 19 22:54:45 CET 2005
Wed Jan 19 22:54:46 CET 2005
Wed Jan 19 22:54:47 CET 2005
Wed Jan 19 22:54:48 CET 2005
Wed Jan 19 22:54:49 CET 2005
Wed Jan 19 22:54:50 CET 2005
Wed Jan 19 22:54:51 CET 2005
Wed Jan 19 22:54:52 CET 2005
Wed Jan 19 22:54:53 CET 2005
Wed Jan 19 22:54:54 CET 2005
Wed Jan 19 22:54:55 CET 2005
Wed Jan 19 22:54:56 CET 2005

On patched 2.6.11-rc1:

[Heh, clock is two times too fast, perhaps that makes ntpdate fail? -- yes.

root@amd:~# dmesg | grep -i time; for i in 1 2 3 4 5; do ntpdate -b tak.cesnet.cz && sleep 10; done ; date && sleep 10 && date; while [ 1 ]; do date; done | uniq
PCI: Setting latency timer of device 0000:00:11.5 to 64
dyn-tick: Enabling dynamic tick timer
dyn-tick: Timer using dynamic tick
19 Jan 22:59:16 ntpdate[1363]: no server suitable for synchronization found
19 Jan 22:59:25 ntpdate[1364]: no server suitable for synchronization found
19 Jan 22:59:34 ntpdate[1365]: no server suitable for synchronization found
19 Jan 22:59:42 ntpdate[1366]: no server suitable for synchronization found
19 Jan 22:59:51 ntpdate[1367]: no server suitable for synchronization found
Wed Jan 19 22:59:51 CET 2005
Wed Jan 19 23:00:01 CET 2005
Wed Jan 19 23:00:01 CET 2005
Wed Jan 19 23:00:02 CET 2005
Wed Jan 19 23:00:03 CET 2005
Wed Jan 19 23:00:04 CET 2005
Wed Jan 19 23:00:05 CET 2005
Wed Jan 19 23:00:06 CET 2005
Wed Jan 19 23:00:07 CET 2005
Wed Jan 19 23:00:08 CET 2005
Wed Jan 19 23:00:09 CET 2005
Wed Jan 19 23:00:10 CET 2005

I used -t 10 to force it to work. Notice that clock is two times too fast.

root@amd:~# dmesg | grep -i time; for i in 1 2 3 4 5; do ntpdate -t 10 tak.cesnet.cz && sleep 10; done ; date && sleep 10 && date; while [ 1 ]; do date; done |
uniq
PCI: Setting latency timer of device 0000:00:11.5 to 64
dyn-tick: Enabling dynamic tick timer
dyn-tick: Timer using dynamic tick
19 Jan 23:03:27 ntpdate[20782]: step time server 195.113.144.238 offset -45.355081 sec
19 Jan 23:03:38 ntpdate[20784]: step time server 195.113.144.238 offset -9.592768 sec
19 Jan 23:03:47 ntpdate[20786]: step time server 195.113.144.238 offset -12.048951 sec
19 Jan 23:04:00 ntpdate[20788]: step time server 195.113.144.238 offset -8.273278 sec
19 Jan 23:04:08 ntpdate[20790]: step time server 195.113.144.238 offset -12.240673 sec
Wed Jan 19 23:04:18 CET 2005
Wed Jan 19 23:04:28 CET 2005
Wed Jan 19 23:04:28 CET 2005
Wed Jan 19 23:04:29 CET 2005
Wed Jan 19 23:04:30 CET 2005
Wed Jan 19 23:04:31 CET 2005
Wed Jan 19 23:04:32 CET 2005
Wed Jan 19 23:04:33 CET 2005
Wed Jan 19 23:04:34 CET 2005
Wed Jan 19 23:04:35 CET 2005
Wed Jan 19 23:04:36 CET 2005
Wed Jan 19 23:04:37 CET 2005
Wed Jan 19 23:04:38 CET 2005
Wed Jan 19 23:04:39 CET 2005
Wed Jan 19 23:04:40 CET 2005

Anything else I should try?

								Pavel
-- 
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!

  parent reply	other threads:[~2005-01-19 22:10 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-01-19  0:05 [PATCH] dynamic tick patch Tony Lindgren
2005-01-19  0:22 ` Lee Revell
2005-01-19  1:04   ` Tony Lindgren
2005-01-19  4:21 ` Benjamin Herrenschmidt
2005-01-19  5:07   ` Tony Lindgren
2005-01-19  5:21     ` Tony Lindgren
2005-01-19  5:44       ` Benjamin Herrenschmidt
2005-01-19  6:26         ` Tony Lindgren
2005-01-19  9:45           ` Pavel Machek
2005-01-19  5:28     ` Benjamin Herrenschmidt
2005-01-19  6:37       ` Tony Lindgren
2005-01-19  7:08         ` Benjamin Herrenschmidt
2005-01-19  7:31           ` Tony Lindgren
2005-01-19 14:11       ` Stephen Frost
2005-01-19 17:17         ` Tony Lindgren
     [not found]         ` <OFDC470564.D4624EB3-ON41256F8E.00512848-41256F8E.005428CC@de.ibm.com>
2005-01-19 17:37           ` Tony Lindgren
2005-01-19  9:43 ` Pavel Machek
2005-01-19 17:13   ` Tony Lindgren
2005-01-19 17:48     ` Andrea Arcangeli
2005-01-19 18:19       ` Tony Lindgren
2005-01-19 19:12         ` Andrea Arcangeli
2005-01-19 19:17           ` Tony Lindgren
2005-01-19 19:34             ` Tony Lindgren
2005-01-19 22:42               ` Andrea Arcangeli
2005-01-19 22:59       ` George Anzinger
2005-01-19 23:17         ` Tony Lindgren
2005-01-20  0:24           ` George Anzinger
2005-01-20  8:04             ` Tony Lindgren
2005-01-20 23:10               ` George Anzinger
2005-01-21 17:35                 ` Tony Lindgren
2005-01-21 20:23                   ` George Anzinger
2005-01-19 23:26         ` Thomas Gleixner
2005-01-19 23:45           ` john stultz
2005-01-20  5:56             ` Thomas Gleixner
2005-01-20  0:39           ` George Anzinger
2005-01-20  3:15         ` Valdis.Kletnieks
2005-01-19 11:36 ` Pavel Machek
2005-01-19 17:11   ` Tony Lindgren
2005-01-19 17:30     ` Arjan van de Ven
2005-01-19 17:41       ` Tony Lindgren
2005-01-19 22:06     ` Pavel Machek [this message]
2005-01-19 23:08       ` Tony Lindgren
2005-01-19 23:46         ` Pavel Machek
2005-01-19 23:53           ` Tony Lindgren
2005-01-19 23:59         ` Pavel Machek
2005-01-20  0:07           ` Tony Lindgren
2005-01-20  0:44             ` Pavel Machek
2005-01-20  0:54             ` Pavel Machek
2005-01-20  7:39               ` Tony Lindgren
2005-01-19 22:20     ` Pavel Machek
2005-01-20  4:02 ` Zwane Mwaikambo
2005-01-21 17:48   ` Tony Lindgren
2005-01-21 18:27     ` Zwane Mwaikambo
2005-01-21 18:38       ` Tony Lindgren
2005-01-21 18:54       ` Pavel Machek
2005-01-21 21:23         ` Zwane Mwaikambo
2005-01-21 21:29           ` Pavel Machek
2005-01-21 20:25       ` George Anzinger
2005-01-21 21:38         ` Zwane Mwaikambo
2005-01-22  7:24           ` George Anzinger

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