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Re: [PATCH] Improve math benchmark infrastructure


On 06/19/2017 12:52 PM, Wilco Dijkstra wrote:
> Improve support for math function benchmarking.  This patch adds
> a feature that allows accurate benchmarking of traces extracted
> from real workloads.  This is done by iterating over all samples
> rather than repeating each sample many times (which completely 
> ignores branch prediction and cache effects).  A trace can be
> added to existing math function inputs via 
> "## name: workload-<name>", followed by the trace.

There are similarities between this and what DJ and the Red Hat glibc
team did for malloc tracing.

We hope to have this merged soon, but were blocked by the recent
CVE work.

One thing that was suggested at LPC2016 was that we could do better
at trace capture time, perhaps getting a histogram of cache behaviour
and then trying to emulate that same density function in the
whole-system benchmark.

Our page touch algorithm in the malloc simulator was too naive and
real access patterns might have drastic consequences on behaviour.

So I think maybe we'll be able to leverage the simulator we have a
bit more in the coming year to do more detailed modelling of a
workload.

-- 
Cheers,
Carlos.


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