Mikael Pettersson writes: > Mikael Pettersson writes: > > I'm seeing what appears to be a recent massive performance regression > > with trunk's gengtype, as compiled and run in stage 2, on ARM V5TE. > > > > Right now 4.7-20110827's stage2 gengtype has been running for almost > > 10 hours on my ARM build machine, but the process is tiny and no swapping > > occurs. To put those 10 hours in perspective, on this machine (1.6 GHz > > ARM V5TE uniprocessor running Linux) I regularly do full bootstraps and > > regression test suite runs for c,c++,ada,fortran in about 18 hours for > > gcc 4.4, about 20 hours for gcc 4.5, about 24 hours for gcc 4.6, and > > about 27 hours for trunk until recently. So 10 hours or more just in > > stage 2 gengtype is suspicious. > > > > I believe 4.7-20110820 also was unusually slow to build, but I didn't > > monitor that build very carefully so can't say if gengtype was involved > > then too. > > It's now been running for almost 21 hours, with no output produced at all. > According to strace it's currently not doing any syscalls, and according > to gdb it's looping in yylex(). I suspect a miscompilation. > > Anyway I'm killing that build now. I have a pile of stable branch > backports to test, after that I might try a regression hunt on trunk.
The regression a) was repeatable, and b) got fixed in 4.7-20110903. I'm not going to investigate this any further, unless I'm forced to do a regression hunt in this date range in the future.
