hi andrew, hi everyone ! as per your request, i fearlessly built and booted 2.5.41 with preemption enabled. although it was my first take at the dev kernel, it went very smoothly :-D anyway, it seems to perform worse than 2.4.20-pre1-lowlatency. it feels very snappy on startup, but under load it is a lot less responsive to user interaction. i have run benno senoner's latencytest on both kernels. you can see the results at http://spunk.dnsalias.org/latencytest . for me, the biggest problem seems to be soft-raid. i have my /var partition striped over 2 scsi disks, and accessing them causes huge latency peaks. is there any chance to get this under control ? i don't have a spare disk around, so i can't easily compare to non-raid, but i'm quite sure it's the source of the problem, because people with similar hardware are doing fine. other than that, there were a few peaks under /proc stress, but they are not easily reproducible. i have not yet tested your mm-patches due to a compile failure (log is attached below). i used http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.41/2.5.41-mm3/2.5.41-mm3.…. if there's any patches to try or more benchmarks to run, let me know. best, jörn *** Hardware: Dual-P3 @ 600Mhz, 512MB PC100 SDRAM, ASUS P2B-DS one 4G IBM DCAS SCSI disk (/), 2 9G COMPAQ SCSI disks (/var, soft-RAID 0), SCSI CDROM and CDR, no IDE devices. Soundcards: SB Live (used during the tests) and Ensoniq 1371 (idle) The audio file that was played back during the tests came over NFS. *** make -f init/Makefile Generating include/linux/compile.h (updated) gcc -Wp,-MD,init/.version.o.d -D__KERNEL__ -Iinclude -Wall -Wstrict-prototypes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common -pipe -mpreferred-stack-boundary=2 -march=i686 -Iarch/i386/mach-generic -fomit-frame-pointer -nostdinc -iwithprefix include -DKBUILD_BASENAME=version -c -o init/version.o init/version.c ld -m elf_i386 -r -o init/built-in.o init/main.o init/version.o init/do_mounts.o ld -m elf_i386 -e stext -T arch/i386/vmlinux.lds.s arch/i386/kernel/head.o arch/i386/kernel/init_task.o init/built-in.o --start-group arch/i386/kernel/built-in.o arch/i386/mm/built-in.o arch/i386/mach-generic/built-in.o kernel/built-in.o mm/built-in.o fs/built-in.o ipc/built-in.o security/built-in.o lib/lib.a arch/i386/lib/lib.a drivers/built-in.o sound/built-in.o arch/i386/pci/built-in.o net/built-in.o --end-group -o .tmp_vmlinux1 fs/built-in.o: In function `isofs_put_super': fs/built-in.o(.text+0x390e5): undefined reference to `unload_nls' fs/built-in.o: In function `isofs_fill_super': fs/built-in.o(.text+0x39f0b): undefined reference to `load_nls' fs/built-in.o(.text+0x39f25): undefined reference to `load_nls_default' fs/built-in.o(.text+0x3a0c6): undefined reference to `unload_nls' fs/built-in.o: In function `wcsntombs_be': fs/built-in.o(.text+0x3c60b): undefined reference to `utf8_wctomb' make: *** [.tmp_vmlinux1] Error 1 -- Jörn Nettingsmeier Kurfürstenstr 49, 45138 Essen, Germany http://spunk.dnsalias.org (my server) http://www.linuxdj.com/audio/lad/ (Linux Audio Developers)