Re: [Xen-devel] Error message using xentrace.

["Thomas Friebel" <thomas.friebel@xxxxxxx>]

On Sun, 2007-04-15 at 14:47 -0400, Parisa Heidari wrote:
> $xentrace_format  /etc/xen/formats < ~/Traces/xentrace.dat > ~/Traces/def1
> Traceback (most recent call last):
>   File "./xentrace_format", line 108, in ?
>     (tsc, event, d1, d2, d3, d4, d5) = struct.unpack(TRCREC, line)
> struct.error: unpack str size does not match format

This happens from time to time. I think the reason is that xentrace
writes the trace records in two steps: first the CPU number and second
the rest of the trace record. When you interrupt (CTRL-C) xentrace
between these two writes then the last trace entry in the file is
incomplete.

If you need to work around this you might want to pause the VM before
stopping xentrace, so you don't interrupt it at work. But I think it is
save to ignore the error.


> However it gives me a file. And the output is like:
> CPU0  1637436031845 (+       0)  do_block               [ domid = 0x00000000,
> edomid = 0x00000000 ]
> CPU0  1637436034822 (+    2977)  unknown (0x000000000002f00e)  [ 0x00000000
> 0x0002f2aa 0x00000000 0x00000000 0x00000000 ]
> CPU0  1637436035370 (+     548)  unknown (0x000000000002f00f)  [ 0x00007fff
> 0x0002f2aa 0x01c9c380 0x00000000 0x00000000 ]

These two event IDs (0x2f00e and 0x2f00f) are defined and used in the
code since changeset 7801. But there has not been a description added to
the formats file yet.

Cheers
  Thomas


-- 
Thomas Friebel
Operating System Research Center
AMD Saxony, Dresden, Germany
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