On Sun, Apr 1, 2012 at 7:49 AM, Vitor Garcia <vitorlopesgarcia@xxxxxxxxx> wrote: > On Sun, 01 Apr 2012 13:37:27 +0200 > Florian Pritz <bluewind@xxxxxxx> wrote: > >> Simple tests (building readline because it's small) with -j4 and -j8 >> on my i7-920 show that -j8 is around 20% faster than -j4. IIRC >> wikipedia states that HT core can increase performance by up to 30%. > > This is nice to know. I work with mechanichal engineering simulations > and we have noted that using more threads then avaiable processors (we > have a 2 x 6 cores processors that has HT, so it looks like a 24 cores > server) increases the calculation time on the softwares we have. I > assumed that the same would apply to any intensive task, and we have > even disabled HT on the BIOS. Perhaps I'll enable it again. from my limited experience with scientific computing, the appropriate number of threads oftens relates not only to the number of cpus/cores, but also to the genuine feature of your application. i would suggest making some smaller-scaled test runs to test the performance and the implementation as well. best regards,
