Re: [Xen-devel] Xenalyze questions

[George Dunlap <dunlapg@xxxxxxxxx>]

On Thu, Jun 6, 2013 at 12:35 PM, Simon Graham <simon.graham@xxxxxxxxxx> wrote:
> I've been trying to use xenalyze to investigate some problems on our Xen 
> 4.2.2 based product and have run into a couple of issues:
>
> First, I ran into problem running xenalyze on 64-bit Linux because some of 
> the trace data structures were not properly packed  - I worked around this by 
> adding the packed attribute where needed but I suspect there is a more 
> elegant solution (see attached patch).
>
> With that out of the way, I am now running it on a trace file and it craps 
> out in the following code because e->pf_case has a large -ve value 
> (presumably uninitialized):
>
> void shadow_mmio_postprocess(struct hvm_data *h)
> {
>     struct pf_xen_extra *e = &h->inflight.pf_xen;
>     if ( opt.summary_info )
>     {
>         if(e->pf_case)
> =>          update_summary(&h->summary.pf_xen[e->pf_case],
>                            h->arc_cycles);
>         else
>             fprintf(warn, "Strange, pf_case 0!\n");
>
>         hvm_update_short_summary(h, HVM_SHORT_SUMMARY_MMIO);
>     }
>
>     if(opt.with_mmio_enumeration)
>         enumerate_mmio(h);
> }



>
> The output from running the program is:
>
> Starting program: /home/sgraham/sandbox/Community/xenalyze/xenalyze 
> ~/tmp/e.evt
> No output defined, using summary.
> Using VMX hardware-assisted virtualization.
> scan_for_new_pcpu: Activating pcpu 0 at offset 0
> Creating vcpu 0 for dom 32768
> scan_for_new_pcpu: Activating pcpu 1 at offset 1560
> Creating vcpu 1 for dom 32768
> scan_for_new_pcpu: Activating pcpu 2 at offset 1772
> Creating vcpu 2 for dom 32768
> scan_for_new_pcpu: Activating pcpu 3 at offset 68428
> Creating vcpu 3 for dom 32768
> scan_for_new_pcpu: Activating pcpu 5 at offset 68520
> Creating vcpu 5 for dom 32768
> scan_for_new_pcpu: Activating pcpu 10 at offset 73632
> Creating vcpu 10 for dom 32768
> scan_for_new_pcpu: Activating pcpu 11 at offset 90588
> Creating vcpu 11 for dom 32768
> init_pcpus: through first trace write, done for now.
> hvm_generic_postprocess_init: Strange, h->postprocess set!

Hmm, it looks like this is the problem here.

Can you try adding this patch, and then running the following?

xenalyze -a -s --tolerance=1 [filename] > [filename.dump]?

The resulting file may be pretty big; I'll just need the last 50 or so lines.

 -George

Attachment: xenalyze-warn-on-postprocess.diff
Description: Binary data

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