This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH v3] Add random memcpy test


On Thursday 23 March 2017 04:45 PM, Wilco Dijkstra wrote:
> The 2nd version of this patch removes the made-up distribution and one based on a real
> trace instead:
> 
> Add a new randomized memcpy test for copies up to 256 bytes.  The distribution of size and
> alignment is based on a trace of SPEC2006 (other traces could be added in the future).
> Instead of repeating the same copy over and over again like the existing tests, it times several
> thousand different copies to more accurately estimate the overhead of branch prediction due to
> the different sizes and alignments.
> 
> ChangeLog:
> 2017-02-09  Wilco Dijkstra  <wdijkstr@arm.com>
> 
>         * benchtests/Makefile (string-benchset): Add memcpy-random.
>         * benchtests/bench-memcpy-random.c: New file.

Nice, this looks good to me.  There may be additional cache effects in
spec2006 that may make these results different from actual spec2006, but
it is still a valuable data point, definitely more than the repeated copies.

Siddhesh


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]