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Re: RFC: Run libm tests separately for each function
On Fri, 17 Feb 2017, Joseph Myers wrote:
> I'd expect this patch to improve test time for sufficiently high
> parallelism, where the move from 17 separately built large tests to 1137
> smaller tests (on x86_64) allows more parallelism that outweighs the
> overheads of running more tests separately from the makefile. And of
> course if you compare with 2.25, that had serialization for the run of
> gen-libm-test.pl (which happened unnecessarily as part of the build rather
> than only when testing because of the before-compile setting).
A single -j12 run before and after the patch (based on current mainline,
so with my move of more functions to auto-libm-test-*) gives timings
before
real 0m27.193s
user 4m27.496s
sys 0m7.988s
and after
real 0m33.617s
user 5m11.500s
sys 0m22.392s
which I consider acceptable (and as noted I'd expect test time to improve
for sufficiently high parallelism on systems with enough CPU cores where
the previous 17 compilations of 50 MB of code had a serializing effect).
--
Joseph S. Myers
joseph@codesourcery.com