Re: Perfctr-Xen framework for permonace analysis

[Keir Fraser <keir.xen@gmail.com>]

On 12/05/2011 20:36, "Ruslan Nikolaev" <nruslan_devel@yahoo.com> wrote:

> Hi
> 
> I want to make an announcement about new perfomance monitoring framework.
> 
> Perfctr-Xen framework that enables per-thread performance analysis in Xen.
> Current version is capable of properly virtualizing counters in both
> paravirtualized and HVM modes. It is based on perfctr (which is a library and
> kernel module for non-virtualized guests), ported to Xen, and extended to work
> properly in virtualized environment. Both accumulative and interrupt modes
> counting (profiling) are supported.
> 
> The advantage of Perfctr-Xen is that it does not require specific HVM
> extensions which are needed for vpmu driver, can work in paravirtualized mode,
> and it also quite universal: works with many common tools such as PAPI,
> HPCToolkit, TAU PerfExplorer. It supports proper per-domain and per-thread
> virtualization. It is light-weight, supports wide range of CPUs, does not
> require save-and-restore for accumulative mode of counting (it uses counter
> offsetting), avoids expensive hypercalls and counter re-programming in certain
> circumstances (when threads are counting the same type of events). In
> addition, some techniques are employed to account for the overhead caused by
> the framework itself. This makes measurements quite accurate.
> 
> Perfctr-Xen consists of series of patches that need to be applied to Xen,
> Linux, perfctr. There are available at:
> http://people.cs.vt.edu/~rnikola/
> 
> The code is available under LGPL. It would be great to discuss if and how it
> can be integrated into Xen.

Could it reasonably replace the oprofile stuff we have already? I wouldn't
want yet another perfctr subsystem/interface unless it supplants an existing
one. We need a revolving door policy here I think.

 -- Keir

> The publication regarding Perfctr-Xen is at:
> http://portal.acm.org/citation.cfm?id=1952687
> 
> Thanks,
> Ruslan Nikolaev
> 
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