On Fri, Aug 5, 2016 at 10:02 PM, Jim Meyering wrote: > On Fri, Aug 5, 2016 at 7:32 PM, Norihiro Tanaka wrote: >> >> On Fri, 5 Aug 2016 13:29:43 -0700 >> Jim Meyering wrote: >> >>> On Fri, Aug 5, 2016 at 4:30 AM, Norihiro Tanaka wrote: >>> > dfaoptimize() is not set fast flag even if it is success, but it is wrong. >>> > If success, dfa matcher uses algorithm for single byte, and it is so fast. >>> > >>> > I think this bug does not affect for grep, but it will affect with the >>> > patch that I just sent to gawk. >>> >>> Thank you for the patch. >>> I was going to push it with the attached slightly updated log message. >>> Note however that grep does use that -> fast member via dfasearch.c's >>> use of the dfaisfast function. >>> But then I realized I should at least verify with "make check", and >>> found that this makes grep's dfa-match test fail. >>> Thus, I will not be pushing it as-is. >> >> Thanks for review and adjustment. I re-ran all tests including dfa-match, >> and they were passwd again in my machine. Next, I will re-run them on >> Fedora24, as my machine is RHEL 6.8 and GCC 4.4.7 which is too old. >> >> However, I do not know why dfa-match test fails on your machine. >> dfa-match test does not use grep. It directly calls dfa functions through >> dfa-match-aux executable in order to test codes of dfa which grep does >> not use. dfa-match-aux does not referer to the ->fast member. > > I have examined the logs, which suggest it was a false positive in a > parallelized "make check" run, due to that test's 3-second timeout. I > have tried repeatedly to reproduce that failure, so far without > success, but in coreutils development, with parallelized tests, we > fixed many hard-to-reproduce tests with small timeout limits like this > -- most of them now use 10 seconds as the limit, so I will change this > one, too (and several others) with the attached patch. > > I have pushed your patch. While trying to reproduce that, I ran some tests on OS X and saw frequent failure of one of the tests, so wrote the attached to work around what I assume is an aggressive write-to-/dev/null optimization: