Dewayne Geraghty
2004-Jun-11 21:58 UTC
P4 (4.10) kernel build performance with/without SMP/APIC_IO/hyperthreading
Re an earlier em thread, "HTTP and SMP" April 2004, I decided to test my out-of-the-box P4 (2.8E) HT threading enabled with SATA HD. Test was to build identical kernels using FreeBSD 4.10 taking note of the compile times. Then reboot with: SMP, APIC_IO in kernel, and machdep.hlt_logical_cpus: 0. In all cases CPU_ENABLE_SSE was also enabled. Summary for two clean kernel builds, using csh time --------------------------------------------------- Kernel build without SMP, APIC_IO, (no variable machdep.hlt_logical_cpus) 1) 143.612u 23.095s 2:52.19 96.8% 1487+2195k 1872+2748io 0pf+0w 2) 143.831u 22.830s 2:55.61 94.9% 1488+2194k 3249+2747io 130pf+0w Kernel build with SMP, APIC_IO, machdep.hlt_logical_cpus=0 3) 145.106u 33.345s 2:57.38 100.5% 1451+2093k 3205+2746io 128pf+0w 4) 146.284u 32.481s 2:50.61 104.7% 1446+2093k 207+2745io 0pf+0w An interesting result - the "run (3)" time was reproduced and revealed that files were being deleted via softupdate, and should be discarded. Experimental error on my part. This didn't affect runs 1 & 2. I repeated run 4 redirecting io to a file to reduce screen delays, but with little difference. # cd ..; rm -R TEST3; cd /sys/i386/conf; config TEST3; cd ../../compile/TEST3; # time make depend all >/tmp/build.lis 146.155u 32.623s 2:50.59 104.7% 1447+2090k 185+2755io 0pf+0w In this test of kernel builds, you'll save around 1.1% of your time using SMP with logical HT CPU's on FreeBSd 4.10. Regards, Dewayne. PS: Of course I attempted to "make -j2 depend all" but this failed as a previous module hadn't completed when needed. e.g. bioscall.s Find local movie times and trailers on Yahoo! Movies. http://au.movies.yahoo.com