On Sat, Nov 06, 2021 at 01:33:29AM +0200, Nir Soffer wrote:
> On Sat, Nov 6, 2021 at 1:23 AM Nir Soffer <[email protected]> wrote:
> >
> > The generic vector reallocs on every append. Add benchmarks to measure
> > the cost with uint32 vector (used for copying extents) and the effect of
> > reserving space upfront.
> >
> > The tests show that realloc is pretty efficient, but calling reserve
> > before the appends speeds the appends up significantly.
> >
> >     NBDKIT_BENCH=1 ./test-vector
> >     bench_reserve: 1000000 appends in 0.004503 s
> >     bench_append: 1000000 appends in 0.014986 s
> >
> > The new benchmarks do not run by default to avoid trouble in CI on
> > overloaded machines or under qemu emulation.
> >
> > A new target added to run all benchmaks:
> >
> >     make bench
> >
> > Ported from libnbd:
> > - https://listman.redhat.com/archives/libguestfs/2021-October/msg00304.html
> > - https://listman.redhat.com/archives/libguestfs/2021-October/msg00305.html
> > ---
> >  Makefile.am                |  5 +++
> >  README                     |  7 ++++
> >  common/utils/Makefile.am   |  3 ++
> >  common/utils/bench.h       | 72 ++++++++++++++++++++++++++++++++++++++
> 
> I forgot to add this file to the sources, so it is not included in the 
> tarball.
> Wil fix this before pusing.
> 
> I think including maintainer-check-extra-dist in the check target wil avoid
> such errors for very little cost:

This rule only works directly after running "make dist".

Rich.

> $ time make dist maintainer-check-extra-dist >/dev/null
> make: *** [Makefile:1173: maintainer-check-extra-dist] Error 1
> 
> real 0m3.767s
> user 0m2.655s
> sys 0m1.644s

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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