Re: [Xen-devel] Xenalyze?

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

The file length itself probably isn't that important, but rather the
fact that longer trace files increase the opportunity for certain
kinds of probabilistic problematic events to occur.

The problem here looks like a problem with TSC skew -- xenalyze is
having trouble figuring out how to process the records in the right
order because of drift in the TSC value across cores (that's what the
"Possible tsc skew" messages are about), and end up breaking an
assumption because it's failing (hence the "FATAL: p->current = NULL"
message) .

Can you give me the cs of the tip of your hg tree?  I'll take a look
and see if I have a local fix.

 -George

On Thu, Jul 8, 2010 at 3:09 PM, Thomas Graves <tgraves@xxxxxxxxxxxxx> wrote:
> Hello,
>
> I'm new to using xentrace and xenalyze and I am having problems running
> xenalyze on a large trace file. It is always giving me a fatal error. If I
> run it on like a 30 second trace it seems to work fine.
>
> Is this a known issue or am I possibly doing something wrong?  Do you think
> it would work if I truncate the file or would it be missing stuff xenalyze
> expects?   If there is no way to truncate it  perhaps I'll see if I can
> modify it to only show me certain time frame - I haven't looked at the code
> yet so I guess I'll have to see if that is possible.
>
> I'm using xen3.4.3 with rhel5.4 dom0 running a rhel5.4 vm.
>
> I'm trying to debug a vm hang at boot which sporadically occurs so I just
> have trace running while I do a bunch of creates and deletes so the trace
> file gets fairly large.  If you have other ideas what might work better I
> would be interested in hearing them.
>
>
> -------
> -bash-3.2$ ls -la trace.raw
> -rw-r--r-- 1 root root 13238044416 Jul  7 23:02 trace.raw
> -bash-3.2$ xenalyze/xenalyze --cpu-hz=2.43G --summary  trace.raw > out
>
> -------
> ..
> ..
> ..
> ..
> runstate_change old_runstate blocked, d1402v0 runstate runnable.  Possible
> tsc skew.
> runstate_change old_runstate blocked, d1402v0 runstate runnable.  Possible
> tsc skew.
> runstate_change old_runstate runnable, d1402v0 runstate running.  Possible
> tsc skew.
>  Not updating.
> FATAL: p->current null
> ]  20f101(20:f:101) 3 [ 802061ea ffffffff f ]
> -----
>
>
> Any help is appreciated,
> Thanks,
> Tom Graves
>
>
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>

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