I'm running the low latency and preemption kernel patches on 2.4.19. I'm getting disk copy latency of around 10ms. Since I'm a real time person (according to M. Goggins) who doesn't use the hd in real time, I can live with this, but it bugs me. I've tried ext2 and ext3, no difference. Any other tips? (Tue Nov 19 15:20:19) (root@head:/home/jfm3/latencytest/latencytest0.42-png) bash> ./do_tests none 3 256 0 350000000 x11perf - X11 performance program, version 1.5 The XFree86 Project, Inc server version 40200000 on :0.0 from head Tue Nov 19 15:20:32 2002 Sync time adjustment is 0.2320 msecs. 2000 reps @ 3.8063 msec ( 263.0/sec): Scroll 500x500 pixels 2000 reps @ 3.8071 msec ( 263.0/sec): Scroll 500x500 pixels 2000 reps @ 3.8092 msec ( 263.0/sec): Scroll 500x500 pixels 2000 reps @ 3.8064 msec ( 263.0/sec): Scroll 500x500 pixels 2000 reps @ 3.8187 msec ( 262.0/sec): Scroll 500x500 pixels 10000 trep @ 3.8095 msec ( 262.0/sec): Scroll 500x500 pixels 120 reps @ 52.5438 msec ( 19.0/sec): ShmPutImage 500x500 square 120 reps @ 52.7976 msec ( 18.9/sec): ShmPutImage 500x500 square 120 reps @ 52.9418 msec ( 18.9/sec): ShmPutImage 500x500 square 120 reps @ 52.8095 msec ( 18.9/sec): ShmPutImage 500x500 square 120 reps @ 52.8810 msec ( 18.9/sec): ShmPutImage 500x500 square 600 trep @ 52.7948 msec ( 18.9/sec): ShmPutImage 500x500 square fragment latency = 1.451247 ms cpu latency = 1.160998 ms 2.1ms ( 0)| 1MS num_time_samples=57348 num_times_within_1ms=57348 factor=100.000000 2MS num_time_samples=57348 num_times_within_2ms=57348 factor=100.000000 PIXEL_PER_MS=155 fragment latency = 1.451247 ms cpu latency = 1.160998 ms 2.0ms ( 0)| 1MS num_time_samples=20877 num_times_within_1ms=20877 factor=100.000000 2MS num_time_samples=20877 num_times_within_2ms=20877 factor=100.000000 PIXEL_PER_MS=155 fragment latency = 1.451247 ms cpu latency = 1.160998 ms 4.6ms ( 2)| 1MS num_time_samples=28116 num_times_within_1ms=28113 factor=99.989330 2MS num_time_samples=28116 num_times_within_2ms=28115 factor=99.996443 PIXEL_PER_MS=155 -rw-r--r-- 1 root root 350000000 Nov 19 15:23 tmpfile fragment latency = 1.451247 ms cpu latency = 1.160998 ms 6.9ms ( 44)| 1MS num_time_samples=68188 num_times_within_1ms=68144 factor=99.935473 2MS num_time_samples=68188 num_times_within_2ms=68144 factor=99.935473 PIXEL_PER_MS=155 -rw-r--r-- 1 root root 350000000 Nov 19 15:23 tmpfile -rw-r--r-- 1 root root 350000000 Nov 19 15:25 tmpfile2 fragment latency = 1.451247 ms cpu latency = 1.160998 ms 6.5ms ( 8)| 1MS num_time_samples=54930 num_times_within_1ms=54921 factor=99.983616 2MS num_time_samples=54930 num_times_within_2ms=54923 factor=99.987257 PIXEL_PER_MS=155 -rw-r--r-- 1 root root 350000000 Nov 19 15:23 tmpfile -rw-r--r-- 1 root root 350000000 Nov 19 15:25 tmpfile2 -- (jfm3 2838 BCBA 93BA 3058 ED95 A42C 37DB 66D1 B43C 9FD0)