Re: Some test results on i386 and x86_64

[Mark Wielaard <mjw@redhat.com>]

Hi Masami,

On Fri, 2009-04-24 at 21:10 -0400, Masami Hiramatsu wrote:
> Mark Wielaard wrote:
> > On Thu, 2009-04-23 at 15:38 -0400, Masami Hiramatsu wrote:
> >> Mark Wielaard wrote:
> >>> On x86_64:
> >>> FAIL: flightrec2 (log file numbers (2, 2))
> >>> FAIL: flightrec2 (log file size (4))
> >> Thanks!
> >> Could you give me a part of systemtap.log?
> > 
> > Attached.
>
> Hmm, it seems that timer.ms(1) was not kicked so frequently
> on xen-kernel.
> ---
>  1000 flightlog.out.0
>   100 flightlog.out.1
> ---
>  1000 flightlog.out.0
>   920 flightlog.out.1
> ---
> 
> Perhaps, timer resolution on xen-kernel may be 10ms or more?

Yes, seems it counts "slower".

On my non-xen i386 machine (2.6.27.21-170.2.56.fc10.i686):
$ stap -e 'global count=0; probe timer.ms(1) { printf("%d: %d\n",
gettimeofday_ms(), count++); if (count > 10) exit(); }'
1240747341878: 0
1240747341879: 1
1240747341880: 2
1240747341881: 3
1240747341882: 4
1240747341883: 5
1240747341884: 6
1240747341885: 7
1240747341886: 8
1240747341887: 9
1240747341888: 10

But on my xen enabled x86_64 machine (2.6.18-128.1.6.el5xen):
$ stap -e 'global count=0; probe timer.ms(1) { printf("%d: %d\n",
gettimeofday_ms(), count++); if (count > 10) exit(); }'
1240747430504: 0
1240747430504: 1
1240747430514: 2
1240747430514: 3
1240747430524: 4
1240747430524: 5
1240747430524: 6
1240747430534: 7
1240747430534: 8
1240747430544: 9
1240747430544: 10

Cheers,

Mark