> > > > Am 03.09.2025 um 17:48 schrieb Jan Hubicka <[email protected]>: > > > > Hi, > > the number of LTO partitions should exceed number of CPUs (or > > hyper-threads) of > > commonly used CPUs. > > Commonly used. But yes, exceeds is quite relative ;). I guess it’s more > like exceeding the maximum number of threads seen on server platforms (with 2 > CPU’s?).
Indeed I don't think most GCC users have 512 threads right now. This is for GCC to be released in 2026 and will stay in common use for few comming years. In the past increasing number of partition helped even machines with fewer threads just because it reduced garbage collection overhead. This does not seem to reproduce anymore for me with GCC or clang builds (which is also why I finally decided not to touch the default for last year). Perhaps number of partitions became too large or startup costs grew considerably. I tried to profile this and did not spot anything obvious. Honza
