On May 4, 2020 3:33:58 PM PDT, Alexander Duyck <alexander.du...@gmail.com> wrote: >On Thu, Apr 30, 2020 at 1:12 PM Daniel Jordan ><daniel.m.jor...@oracle.com> wrote: >> /* >> - * Initialize and free pages in MAX_ORDER sized increments so >> - * that we can avoid introducing any issues with the buddy >> - * allocator. >> + * More CPUs always led to greater speedups on tested >systems, up to >> + * all the nodes' CPUs. Use all since the system is >otherwise idle now. >> */ > >I would be curious about your data. That isn't what I have seen in the >past. Typically only up to about 8 or 10 CPUs gives you any benefit, >beyond that I was usually cache/memory bandwidth bound.
I've found pretty much linear performance up to memory bandwidth, and on the systems I was testing, I didn't saturate memory bandwidth until about the full number of physical cores. From number of cores up to number of threads, the performance stayed about flat; it didn't get any better or worse. - Josh
