On Fri, Jan 30, 2015 at 10:59:17PM +0000, Ken Moffat wrote: > On Thu, Jan 29, 2015 at 12:23:56AM +0000, Ken Moffat wrote: > > > > gcc: 125 unexpected failures in g++, 658 in gcc, 22 in libstdc++ > > instead of the usual handful of failures. The last time I saw those > > sorts of numbers was a little while before my AmigaOne expired. > > > I wonder if some of it was because my tmpfs for /tmp was too small. > I thought I was using 6GB, but I was on my 7.6 system when I set > that up, the November system I used to build the new one was still > using only 2GB for /tmp. > > I've now rebuilt gcc on the completed system, again using only 2GB > for the tmpfs. This time, the results were a little better - only > 83 unexpected failures in gcc, and 42 in g++, none in libstdc++. > In both cases, I used -j4. > [ cut the context there! ]
I did further testing, and never managed to pin down what was causing the varying number of failures (and I could not see any evidence for what the tests actually returned or should have returned - I'm sure it was there somewhere, but I do not really want to become more acquainted with gcc's testsuite. At one time, using -j1 looked as if it would help, but in the end it was still unreliable. In particular, building on a real spinning disk did NOT seem to help. All that repeated testing was x86_64. On Friday night I built 7.7 i686 in qemu. Because I could not work out how to make the box suspend when the qemu session had completed, I built with -j1. It looked pretty good, just 4 failures in g++. Tonight I've been rerunning the tests on a completed system, still in qemu. It occurred to me that some of the failures might be sub-architecture specific. So, for the first run I continued with the 'kvm64' CPU and used -j4 : g++ was the same, but gcc now reported 31 unexpected failures, and all bar two were in gomp. In other words, either the failures are random, or using -j4 instead of -j1 for the tests causes more failures. Then I decided to run with -j4 and --cpu=host (this is a Phenom x4). For gcc, 149 unexpected failures, apparently all in gcc.dg/c99-typespec-1.c. For g++, the same 4 failures as before (asan/asan_test.C and 3 from pr61160-3.C). Even running with -j4, this takes a significant amount of time, I don't think I can justify spending more time looking at different qemu host values and playing with -j1 or -j4 for the tests when the box is supposed to be building 7.7 x86_64 for itself on bare metal. There is also a possibility that there are one or more races in the tests, and results might be random. But I think I will change my script to use -j1 for the tests. ĸen -- Nanny Ogg usually went to bed early. After all, she was an old lady. Sometimes she went to bed as early as 6 a.m. -- http://lists.linuxfromscratch.org/listinfo/lfs-dev FAQ: http://www.linuxfromscratch.org/faq/ Unsubscribe: See the above information page
