RE: [Xen-devel] Time went backwards errors booting unstable cs 17557with 64GB memory

["Carb, Brian A" <Brian.Carb@xxxxxxxxxx>]

Setting clocksource=pit removes the errors and allows a clean boot, as
does setting dom0_mem=4096M.  What are the implications of running with
a different clocksource?

FYI setting xenheap_megabytes=64 by itself does not eliminate the timer
errors..

brian carb
unisys corporation - malvern, pa

-----Original Message-----
From: Bill Burns [mailto:bburns@xxxxxxxxxx] 
Sent: Tuesday, May 06, 2008 11:40 AM
To: Carb, Brian A
Cc: xen-devel
Subject: Re: [Xen-devel] Time went backwards errors booting unstable cs
17557with 64GB memory

Carb, Brian A wrote:
> I've built the latest xen unstable cs 17557 to run on a multi-cell 
> ES7000/one. When I boot with the procs and memory from a single cell 
> (4 cores aka 8 cpus from cell0, 32gb memory from cell0), dom0 boots 
> cleanly . However, if I use the memory from 2 cells (4 cores aka 8 
> cpus from cell0, 64gb memory interleaved from cell0 & cell1), dom0 
> boots eventually, but produces multiple Timer errors as shown below. I

> tried setting numa=on but timer errors persist. FYI Xen unstable cs 
> 17318 ran successfully without timer errors on this multi-cell
configuration.
> 
> Timer ISR/0: Time went backwards: delta=-2679966594 delta_cpu=10033406
> shadow=13664567457 off=530033587 processed=16874567457
> cpu_processed=14184567457
> 0: 14184567457
> 1: 16874567457
> 2: 16874567457
> 3: 16874567457
> 4: 16874567457
> 5: 16874567457
> 6: 16874567457
> 7: 16874567457
> 
> The attached serial trace shows a boot with 32gb and then a boot with 
> 64gb.
> 

Is the system using the pm timer? You may try clocksource=pit, or
keeping more memory in the Hypervisor (via xenheap or dom0_mem) as
workarounds.

 Bill

> brian carb
> unisys corporation - malvern, pa
> 
>  
> 
> 
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> 
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