FSB - Dostávám zajímavé výsledky v závislosti na jádře:
(2PC s identickým HW) počet threadů 1 až 90
for ((x=0;x<90;x++)) { time dd if=/dev/zero of=/dev/null bs=1048576 count=10000 & }
uname -a
Linux alfa 2.6.18.8-xen #1 SMP Tue Sep 30 07:53:31 CEST 2008 x86_64 GNU/Linux
time dd if=/dev/zero of=/dev/null bs=1048576 count=10000
1, 10485760000 bytes (10 GB) copied, 2.99504 seconds, 3.5 GB/s = 3,5 GB/s
2, 10485760000 bytes (10 GB) copied, 4.59596 seconds, 2.3 GB/s = 4,6 GB/s
3, 10485760000 bytes (10 GB) copied, 4.96224 seconds, 2.1 GB/s = 6,2 GB/s
4, 10485760000 bytes (10 GB) copied, 5.77682 seconds, 1.8 GB/s = 7,2 GB/s
5, 10485760000 bytes (10 GB) copied, 6.10528 seconds, 1.7 GB/s = 8,5 GB/s
6, 10485760000 bytes (10 GB) copied, 7.2217 seconds, 1.5 GB/s = 9 GB/s
7, 10485760000 bytes (10 GB) copied, 9.30288 seconds, 1.1 GB/s = 7,7 GB/s
8, 10485760000 bytes (10 GB) copied, 11.1839 seconds, 0,94 = 7.5 GB/s
9, 10485760000 bytes (10 GB) copied, 12.1225 seconds, 0,85 (0.76-0.95) = 7,7 GB/s
90, 10485760000 bytes (10 GB) copied, 127.107 seconds, 0,08 (0.07-0.08) = 7,2 GB/s by woko
uname -a
Linux astra 2.6.26-1-amd64 #1 SMP Wed Sep 10 15:31:12 UTC 2008 x86_64 GNU/Linux
1, 10485760000 bytes (10 GB) copied, 0.995522 s, 10.5 GB/s = 10.5 GB/s
2, 10485760000 bytes (10 GB) copied, 0.994499 s, 10.6 GB/s = 21.2 GB/s
3, 10485760000 bytes (10 GB) copied, 0.977325 s, 10.7 GB/s = 32.1 GB/s
4, 10485760000 bytes (10 GB) copied, 0.99796 s, 8,97 (7,8-10.5) = 35,9 GB/s
5, 10485760000 bytes (10 GB) copied, 0.977671 s, 9,58 (8.1-10,7) = 47,9 GB/s
6, 10485760000 bytes (10 GB) copied, 0.999366 s, 8,93 (8,1-10.5) = 53,6 GB/s
7, 10485760000 bytes (10 GB) copied, 0.999054 s, 8,44 (8,1-10.5) = 59,1 GB/s
8, 10485760000 bytes (10 GB) copied, 1.27825 s, 8.2 GB/s = 65,6 GB/s
9, 10485760000 bytes (10 GB) copied, 1.28976 s, 7,13 (5.9-8,1) = 64,2 GB/s
90, 10485760000 bytes (10 GB) copied, 13.8611 s, 0,74 (0,7-0,8) = 66,6 GB/s by woko
a pro porovnání zopakuji na tomto stroji alespoň jeden minulý test CPU ve 40ti vláknech
for ((x=0;x<40;x++)) { dd if=/dev/urandom of=/dev/null bs=1048576 count=10 & }
10485760 bytes (10 MB) copied, 93.7754 s, 112 kB/s
..
10485760 bytes (10 MB) copied, 94.3177 s, 111 kB/s
= 4,44 MB/s (na 2.6.18-8-xen 2,3MB/s)