Stan Hoeppner <s...@hardwarefreak.com> writes: > > Depending on the size of the photos one is converting, if they're relatively > small like my 8.3MP 1.8MB jpegs, I'd think something like a dual core Phenom > II > X2 w/ 6MB L3 cache and 21.4 GB/s memory b/w would likely continue to scale > with > reduced overall script run time up to 4 parallel convert processes, maybe > more, > due to the "excess" of L3 cache and the 10.7 GB/s available to each core. > > Conversely, I'd think that a quad core Athlon II X4 with no L3 cache and only > 512KB L2 cache per core, with each core receiving effectively only 5.3 GB/s of > b/w, would not scale effectively to core_count*2 parallel processes as the > Phenom II X2 would. In fact, due to 4 cores with little cache sharing the > same > 21.4 GB/s of memory b/w, the quad core Athlon II would probably start seeing a > decline in reduced run time going from 2 processes to 4 as twice as many cores > compete for memory access, and tailing off dramatically as the process count > is > increased to 5 and up. > > Just a guess. Anyone have such systems to test with? :)
I have an Athlon II X4 620 (2.6 GHz), so I ran your test. It is somewhat different since I am currently running FreeBSD and didn't want to reboot to get back into debian, and I have GraphicsMagick instead of ImageMagick, but that shouldn't change the basic results. The results were that the time decreased up to 4 processes, but remained unchanged after that. Processors Time (seconds) P1 66 P2 36 P3 25 P4 20 P5 20 P6 20 P7 20 P8 20 I am sure the time would have increased if the system had run out of memory and had to start swapping. The system is not completely idle since I am running a KDE 4.4.5 desktop and VirtualBox with two guest OSs (Debian and NetBSD). I suspect it would have closer to linear scaling if the system had been completely idle. -- Carl Johnson ca...@peak.org -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/87oc7k4si5.fsf@oak.localnet
