| |
|
 |
|
 |
|
|
|
| |
|
|
xen-devel
Re: [Xen-devel] system time skew measurement patch
On 21/4/08 22:00, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:
> The patch below printk's useful interprocessor system time skew
> information. Patch is relative to xen-unstable. Printk is
> rate-limited to output only when O(max skew) grows. Max skew
> is measured across all cores/processors... ideally eventually it
> should be measured for each processor and exported via "xm info"
> so groups of sync'ed processors can be properly identified.
>
> Even on my Core 2 Duo E6850 @ 3.00 GHz (1 socket), I am seeing
> skew on the order of 6000 cycles (2 usec). I'm not clear on
> whether this is due to the calibration algorithm or the
> hardware.
This is not unexpected. Stick a max() function at the end of get_s_time()
and we'll be fine.
-- Keir
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
| |
|
Home