On 2016.09.23 at 15:29 +0200, Richard Biener wrote: > > > > So 50000 looks too big to me. > > I think the issue is that the default number of partitions is too high > (32) which pessimizes 4-core machines if the units are too small.
The more partitions are used the less memory is required at LTRANS time. If for example you limit partitions to 4 on a 4-core machine with 8GB memory, you would start swapping when building Firefox. And even lto-partitions=8 is slower than the default of 32: (Firefox libxul build times with gcc-6.) --param=lto-partitions=8 -flto=4: 1670.19s user 23.39s system 305% cpu 9:14.13 total default -flto=4: 1668.94s user 32.51s system 320% cpu 8:50.36 total If someone wants fewer partitions he can use -flto-partition=one/none or --param=lto-partitions=1. -- Markus
