Re: [Xen-devel] Perfctr-Xen framework for permonace analysis

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

On Thu, May 12, 2011 at 9:35 PM, Ruslan Nikolaev
<nruslan_devel@xxxxxxxxx> wrote:
> Well, at least it can peacefully coexist with oprofile. AFAIK, XenOProf has 
> some limitations (system wide monitoring only), and works only with OProfile. 
> Many people would also prefer to use PAPI/HPCToolkit/PerfExplorer. HPCToolkit 
> itself is quite sophisticated framework with elaborated functionality. It is 
> quite comparable to OProfile. PerfExplorer is also a very interesting 
> project. PAPI is used by developers to do wide range of measurements which 
> are not necessarily possible with OProfile. The key feature of Perfctr-Xen is 
> that it allows to do all levels of performance monitoring, it does not 
> restrict to profiling.

xenoprof enables the normal Linux oprofile, which can be used on
processes, as well as on domains and on Xen itself.  I don't remember
if oprofile allows collection of performance counters on individual
processes though; I suspect not.

I'm a bit torn -- if people are used to using oprofile under Linux, it
may be advantageous to keep that, rather than replacing it outright
with a new tool.  But as you said about the scheduler, Keir, oprofile
gets little enough love as it is...

 -George

>
> This framework and xenoprof provide orthogonal solutions which both can be 
> used in different circumstances.
>
> Thanks,
> Ruslan Nikolaev
>
> --- On Fri, 5/13/11, Keir Fraser <keir.xen@xxxxxxxxx> wrote:
>
>> From: Keir Fraser <keir.xen@xxxxxxxxx>
>> Subject: Re: [Xen-devel] Perfctr-Xen framework for permonace analysis
>> To: "Ruslan Nikolaev" <nruslan_devel@xxxxxxxxx>, 
>> xen-devel@xxxxxxxxxxxxxxxxxxx
>> Date: Friday, May 13, 2011, 12:09 AM
>> On 12/05/2011 20:36, "Ruslan
>> Nikolaev" <nruslan_devel@xxxxxxxxx>
>> 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
>> >
>> > _______________________________________________
>> > Xen-devel mailing list
>> > Xen-devel@xxxxxxxxxxxxxxxxxxx
>> > http://lists.xensource.com/xen-devel
>>
>>
>>
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>>
>
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