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Re: RFA: revert libstdc++ r205810: simulator workload increase caused regression
- From: Hans-Peter Nilsson <hans-peter dot nilsson at axis dot com>
- To: jwakely dot gcc at gmail dot com
- Cc: Yufeng dot Zhang at arm dot com, libstdc++ at gcc dot gnu dot org, Renlin dot Li at arm dot com, gcc-patches at gcc dot gnu dot org
- Date: Sun, 15 Dec 2013 15:20:48 +0100
- Subject: Re: RFA: revert libstdc++ r205810: simulator workload increase caused regression
- Authentication-results: sourceware.org; auth=none
> From: Jonathan Wakely <jwakely.gcc@gmail.com>
> Date: Sun, 15 Dec 2013 11:38:43 +0100
> On Dec 15, 2013 6:57 AM, "Hans-Peter Nilsson"
> <hans-peter.nilsson@axis.com> wrote:
> >
> > From the revision range 205803:205810 (excluding:including) an
> > on, my autotester for cris-elf reports a regression:
> >
> > Running /tmp/hpautotest-gcc1/gcc/libstdc++-v3/testsuite/libstdc++-dg/conformance.exp ...
> > WARNING: program timed out.
> > FAIL: 20_util/hash/chi2_quality.cc execution test
> >
> > This appears to have come from revision r205810. I can't find
> > the discussion
>
> http://gcc.gnu.org/ml/libstdc++/2013-10/msg00233.html
>
> > or approval leading to that commit.
>
> http://gcc.gnu.org/ml/libstdc++/2013-11/msg00098.html
Aha, October and November; for gcc-patches I looked like a month
back but for that list alone I only looked at December, sorry.
An ill-formed test for the chi2 value to be
math-implementation-dependent, IMHO (certainly not obvious to
me), and it'd have been a service to others mentioning this
oddness in the patch.
I'll take the statement "pass for all arm target linking with
glibc" at face value and not bring up soft-float variants on
newlib and slower host machines (oops).
The time-eater I noticed at the time I added the
SAMPLES-for-simulators thingy is actually in test_document_words.
Would it be ok to split up chi2_quality.cc in five, along the
test_*() functions?
Maybe with a comment or two about the sensitivity to the number
of iterations in test_uniform_random() and test_bit_flip_set().
That will, if not take out the simulator timeout issue
altogether, then at least make it specific to the part with
test_document_words().
Before I thought of that, I started a run for arm-eabi (oops
again, not glibc) with the following patch, presented without a
ChangeLog entry for your disproval.
Index: libstdc++-v3/testsuite/20_util/hash/chi2_quality.cc
===================================================================
--- libstdc++-v3/testsuite/20_util/hash/chi2_quality.cc (revision 205997)
+++ libstdc++-v3/testsuite/20_util/hash/chi2_quality.cc (working copy)
@@ -1,7 +1,11 @@
// { dg-options "-std=gnu++0x" }
// Use smaller statistics when running on simulators, so it takes less time.
-// { dg-options "-std=gnu++0x -DSAMPLES=30000" { target simulator } }
+// There's also an issue with "VERIFY( chi2 < k*1.1 )" failing for
+// test_uniform_random() and test_bit_flip_set() for SAMPLES=10000
+// and some target library implementations, where 30000 pass.
+// { dg-options "-std=gnu++0x -DSAMPLES=30000" { target { { arm*-* } && simulator } } }
+// { dg-options "-std=gnu++0x -DSAMPLES=10000" { target simulator } }
// Copyright (C) 2010-2013 Free Software Foundation, Inc.
//
brgds, H-P