From: Csdncannon <csdncannon@gmail.com>
To: linuxppc-dev@ozlabs.org, zhouminggang@hotmail.com
Subject: Re: Continual reading from the PowerPc time base register is not stable
Date: Sat, 10 Apr 2010 11:14:09 +0800 [thread overview]
Message-ID: <o2y43c137a81004092014z1511cecdxb7154825dc07b49f@mail.gmail.com> (raw)
In-Reply-To: <43c137a81003241941p84cba56y3e02e40cb22623e2@mail.gmail.com>
[-- Attachment #1.1: Type: text/plain, Size: 769 bytes --]
Sorry, I attached the wrong log, this attachment is the right one.
2010/3/25 Csdncannon <csdncannon@gmail.com>
> In my program, the value of the 64-bit time base register is read
> out, and you will find the later value is even smaller than the earlier
> value from the log “log_timebase”. While the kernel depends on the accuracy
> of the timebase for the compensation of the lost PIT interrupt, the negative
> value between two continual timebase reading will bring to the jump of the
> jiffies. And this timebase problem will bring to the instability of the
> gettimeofday system call.
>
> Do you have any idea about this problem, thanks for your any
> advice. Attached is the code and log.
>
>
> Thanks
>
> Gino
>
>
>
>
[-- Attachment #1.2: Type: text/html, Size: 1744 bytes --]
[-- Attachment #2: gettime.log --]
[-- Type: application/octet-stream, Size: 939 bytes --]
root@tlab8378:/root> /mnt/server/Gino/gettime
1270540744 , 1270540744
Failed : timeout 1270540749 , now 1270558341
Serious : timeout 1270558341 , now 1270540749
1270540755 , 1270540755
1270540765 , 1270540765
Failed : timeout 1270540774 , now 1270558366
Serious : timeout 1270558366 , now 1270540774
1270540775 , 1270540775
1270540786 , 1270540786
1270540796 , 1270540796
Failed : timeout 1270540802 , now 1270558394
Serious : timeout 1270558394 , now 1270540802
Failed : timeout 1270540803 , now 1270558395
Serious : timeout 1270558395 , now 1270540803
1270540806 , 1270540806
Failed : timeout 1270540814 , now 1270558406
Serious : timeout 1270558406 , now 1270540814
1270540816 , 1270540816
1270540827 , 1270540827
1270540837 , 1270540837
1270540847 , 1270540847
Failed : timeout 1270540855 , now 1270558447
Serious : timeout 1270558447 , now 1270540855
1270540858 , 1270540858
next prev parent reply other threads:[~2010-04-10 3:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-25 2:41 Continual reading from the PowerPc time base register is not stable Csdncannon
2010-03-25 8:21 ` Benjamin Herrenschmidt
2010-03-25 10:05 ` Arnd Bergmann
2010-03-25 15:00 ` Csdncannon
2010-03-25 20:38 ` Benjamin Herrenschmidt
2010-03-26 1:11 ` Csdncannon
2010-03-26 1:22 ` Segher Boessenkool
2010-03-26 2:01 ` Csdncannon
2010-03-26 8:52 ` Segher Boessenkool
2010-03-26 9:01 ` Segher Boessenkool
2010-03-26 12:14 ` Csdncannon
2010-04-06 8:02 ` Csdncannon
2010-03-26 1:55 ` Benjamin Herrenschmidt
2010-03-26 2:04 ` Csdncannon
2010-03-25 22:00 ` Chris Friesen
2010-03-25 22:57 ` Benjamin Herrenschmidt
2010-03-25 23:37 ` Kumar Gala
2010-03-25 21:37 ` Segher Boessenkool
2010-04-10 3:14 ` Csdncannon [this message]
2010-04-22 0:44 ` Kim Phillips
2010-04-22 0:50 ` Benjamin Herrenschmidt
2010-04-22 23:27 ` Kim Phillips
2010-04-23 10:57 ` Csdncannon
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