Re: [Qemu-devel] [PATCH v9 0/7] trace: Optimize per-vCPU TCG tracing states

[Stefan Hajnoczi]

On Mon, Jul 10, 2017 at 01:07:44PM +0100, Stefan Hajnoczi wrote:
> On Mon, Jun 26, 2017 at 06:04:34PM -0400, Emilio G. Cota wrote:
> > v8: https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg02335.html
> > 
> > Changes from v8:
> > 
> > - Rebased on top of the current tracing tree -- the one that includes
> >   Lluis' fix (2c321e3c486).
> > - Added Lluis' R-b tag.
> > - Added perf numbers in the commit log of the last patch (tl;dr: no 
> > overhead).
> > 
> > Thanks,
> > 
> >             Emilio
> > 
> > PS. How to quickly get some linux-user perf numbers:
> > 
> > I used dbt-bench[1] for a before/after comparison. I added a script to that
> > repo (breakdown.pl, see below) to make it play well with barchart[2].
> > Obtaining a comparison bar chart is quite simple:
> > 
> > 1. Generate one dbt-bench output file per QEMU checkout, e.g.:
> >   $ git checkout orig && make
> >   [ orig == "before"; new == "after" ]
> >   $ ./dbt-bench.pl /path/to/qemu/build/qemu-x86_64 > orig.out
> >   [ then do the same with orig-disabled, new, etc.]
> >   [...]
> >   $ ls *.out
> >   new-disabled.out  new.out  orig-enabled.out  orig.out
> > 
> > 2. Call dbt-bench's breakdown.pl script with the --barchart option, then
> >   pipe the output to barchart, and finally pipe to gnuplot:
> >   $ ./breakdown.pl --barchart orig.out orig-enabled.out new.out 
> > new-disabled.out \
> >     | ../barchart/barchart.pl --extra-gnuplot='set term dumb 140 30' \
> >          --extra-gnuplot='set title "NBench score; higher is better"' \
> >     | gnuplot
> > 
> > Note that barchart is just a front-end for gnuplot >=5, so any valid term 
> > will
> > work (e.g. 'set term pngcairo size 1200,500').
> > 
> > [1] https://github.com/cota/dbt-bench
> > [2] https://github.com/cota/barchart
> > 
> 
> Thanks, applied to my tracing tree:
> https://github.com/stefanha/qemu/commits/tracing

By the way, I applied your most recent version of this series today :).

Stefan

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