* [patch 5/7] Remove duplicate file in Documentation/networking (drivers_net_wan_Kconfig)
@ 2005-05-28 23:17 domen
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
0 siblings, 1 reply; 6+ messages in thread
From: domen @ 2005-05-28 23:17 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel, Tobias Klauser, domen
[-- Attachment #1: delete-Documentation_networking_wanpipe.txt_drivers_net_wan_Kconfig --]
[-- Type: text/plain, Size: 972 bytes --]
From: Tobias Klauser <tklauser@nuerscht.ch>
wanpipe.txt and wan-router.txt in Documentation/networking
contain the exact same information (diff between the two shows no
difference). This patch removes the reference to this document in
drivers/net/wan/Kconfig.
Signed-off-by: Tobias Klauser <tklauser@nuerscht.ch>
Signed-off-by: Domen Puncer <domen@coderock.org>
---
Kconfig | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
Index: quilt/drivers/net/wan/Kconfig
===================================================================
--- quilt.orig/drivers/net/wan/Kconfig
+++ quilt/drivers/net/wan/Kconfig
@@ -435,7 +435,7 @@ config VENDOR_SANGOMA
the driver to support.
If you have one or more of these cards, say M to this option;
- and read <file:Documentation/networking/wanpipe.txt>.
+ and read <file:Documentation/networking/wan-router.txt>.
To compile this driver as a module, choose M here: the
module will be called wanpipe.
--
^ permalink raw reply [flat|nested] 6+ messages in thread
* The values of gettimeofday() jumps.
2005-05-28 23:17 [patch 5/7] Remove duplicate file in Documentation/networking (drivers_net_wan_Kconfig) domen
@ 2005-05-29 1:37 ` Liangchen Zheng
2005-05-29 1:36 ` Lee Revell
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Liangchen Zheng @ 2005-05-29 1:37 UTC (permalink / raw)
To: linux-kernel
Hello,
We have several SMP machines (Tyan Tiger MPX motherboard, 2
AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
sensitive programs, I observed that the values of gettimeofday () jumped
sometimes on a couple of machines (other machines are fine), from
several hundreds milliseconds to a couple of seconds.
I searched online and tried to figure out why this happened. It
seems there are a lot of people who complained about the clock drift
issue of gettimeofday () on SMP machines. But I still could not get the
answers about what is the exact cause of this issue and how to fix it.
Could somebody tell me some clues? Can this be solved by
upgrading the kernel to 2.6? Thanks a lot.
By the way, I have read Linux SMP HOWTO and the following documents.
http://seclists.org/lists/linux-kernel/2002/Jun/1524.html
http://seclists.org/lists/linux-kernel/2002/Jun/1550.html
http://alphalinux.org/archives/linux-alpha/April2000/0015.html
I could not get enough clues from them yet, maybe because my limited
knowledge about the kernel.
Regards,
[Liangchen Zheng]
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: The values of gettimeofday() jumps.
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
@ 2005-05-29 1:36 ` Lee Revell
2005-05-29 7:42 ` Arjan van de Ven
2005-05-30 9:55 ` P
2 siblings, 0 replies; 6+ messages in thread
From: Lee Revell @ 2005-05-29 1:36 UTC (permalink / raw)
To: Liangchen Zheng; +Cc: linux-kernel
On Sat, 2005-05-28 at 18:37 -0700, Liangchen Zheng wrote:
> Hello,
> We have several SMP machines (Tyan Tiger MPX motherboard, 2
> AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
> sensitive programs, I observed that the values of gettimeofday () jumped
> sometimes on a couple of machines (other machines are fine), from
> several hundreds milliseconds to a couple of seconds.
Are you running NTP on those machines by any chance?
Lee
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: The values of gettimeofday() jumps.
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
2005-05-29 1:36 ` Lee Revell
@ 2005-05-29 7:42 ` Arjan van de Ven
2005-06-02 1:18 ` Liangchen Zheng
2005-05-30 9:55 ` P
2 siblings, 1 reply; 6+ messages in thread
From: Arjan van de Ven @ 2005-05-29 7:42 UTC (permalink / raw)
To: Liangchen Zheng; +Cc: linux-kernel
On Sat, 2005-05-28 at 18:37 -0700, Liangchen Zheng wrote:
> Hello,
> We have several SMP machines (Tyan Tiger MPX motherboard, 2
> AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
> sensitive programs, I observed that the values of gettimeofday () jumped
> sometimes on a couple of machines (other machines are fine), from
> several hundreds milliseconds to a couple of seconds.
try "notsc" as boot option
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: The values of gettimeofday() jumps.
2005-05-29 7:42 ` Arjan van de Ven
@ 2005-06-02 1:18 ` Liangchen Zheng
0 siblings, 0 replies; 6+ messages in thread
From: Liangchen Zheng @ 2005-06-02 1:18 UTC (permalink / raw)
To: 'Arjan van de Ven'; +Cc: linux-kernel
The clock drift disappeared after booting the kernel with
"notsc" option.
Thanks a lot. It seems there is some bug with the TSC support inside
the kernel.
Maybe it is caused by the clock drifts between two TSCs in the both
CPUs, as mentioned by Pádraig Brady in one reply to my previous
question.
But I am still wondering why the clock drift can be so huge (a
couple of seconds sometimes) and the drifts occurred so regular (around
every 1 second).
If I have time in future, I will dig into it to figure out what is the
exact reason.
Thanks a lot for your suggestions.
Regards,
Liangchen
-----Original Message-----
From: Arjan van de Ven [mailto:arjan@infradead.org]
Sent: Sunday, May 29, 2005 12:42 AM
To: Liangchen Zheng
Cc: linux-kernel@vger.kernel.org
Subject: Re: The values of gettimeofday() jumps.
On Sat, 2005-05-28 at 18:37 -0700, Liangchen Zheng wrote:
> Hello,
> We have several SMP machines (Tyan Tiger MPX motherboard, 2
> AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
> sensitive programs, I observed that the values of gettimeofday ()
jumped
> sometimes on a couple of machines (other machines are fine), from
> several hundreds milliseconds to a couple of seconds.
try "notsc" as boot option
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: The values of gettimeofday() jumps.
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
2005-05-29 1:36 ` Lee Revell
2005-05-29 7:42 ` Arjan van de Ven
@ 2005-05-30 9:55 ` P
2 siblings, 0 replies; 6+ messages in thread
From: P @ 2005-05-30 9:55 UTC (permalink / raw)
To: Liangchen Zheng; +Cc: linux-kernel
Liangchen Zheng wrote:
> Hello,
> We have several SMP machines (Tyan Tiger MPX motherboard, 2
> AthlonMP 1900+ CPU, linux-2.4.21-20.EL). When running some time
> sensitive programs, I observed that the values of gettimeofday() jumped
> sometimes on a couple of machines (other machines are fine), from
> several hundreds milliseconds to a couple of seconds.
That sounds like what I described here:
http://lkml.org/lkml/2005/4/4/57
2 options as far as I can see.
1. Use irq affinity to bind the timer irq to a particular CPU,
while using CPU affinity to bind your process to a particular CPU.
2. Change the code to maintain a last_tsc_low for each CPU.
--
Pádraig Brady - http://www.pixelbeat.org
--
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2005-06-02 1:17 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-05-28 23:17 [patch 5/7] Remove duplicate file in Documentation/networking (drivers_net_wan_Kconfig) domen
2005-05-29 1:37 ` The values of gettimeofday() jumps Liangchen Zheng
2005-05-29 1:36 ` Lee Revell
2005-05-29 7:42 ` Arjan van de Ven
2005-06-02 1:18 ` Liangchen Zheng
2005-05-30 9:55 ` P
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox