Joe Landman wrote:
We are working on a machine with 2 Opteron 2218s. For laughs, I ran
streams on it. Here are 1,2,3,4 processor data.
I have a opteron 2220 handy with DDR2-667. At least I'm pretty sure
it's DDR2-667. I multiplied the default N by a factor of 10 to get timings
similar to yours.
1 processor:
Copy: 5713.9944 0.0591 0.0560 0.0600
Scale: 5713.9822 0.0587 0.0560 0.0600
Add: 5454.2389 0.0911 0.0880 0.0920
Triad: 5454.1576 0.0916 0.0880 0.0920
Function Rate (MB/s) Avg time Min time Max time
Copy: 6615.1324 0.0484 0.0484 0.0484
Scale: 6665.6930 0.0480 0.0480 0.0481
Add: 6147.8462 0.0781 0.0781 0.0781
Triad: 6175.3782 0.0777 0.0777 0.0778
2 processors:
Function Rate (MB/s) Avg time Min time Max time
Copy: 5713.8788 0.0591 0.0560 0.0640
Scale: 5713.9822 0.0596 0.0560 0.0640
Add: 5713.9538 0.0858 0.0840 0.0880
Triad: 5713.9538 0.0871 0.0840 0.0880
Obviously using 2 sockets (not 2 cores on 1 socket):
Function Rate (MB/s) Avg time Min time Max time
Copy: 11836.5091 0.0270 0.0270 0.0270
Scale: 11685.2307 0.0274 0.0274 0.0274
Add: 11923.6815 0.0403 0.0403 0.0403
Triad: 11972.4659 0.0401 0.0401 0.0401
4 processors:
Copy: 11428.1834 0.0293 0.0280 0.0320
Scale: 11428.1347 0.0298 0.0280 0.0320
Add: 10908.5812 0.0449 0.0440 0.0480
Triad: 10908.6107 0.0440 0.0440 0.0440
Function Rate (MB/s) Avg time Min time Max time
Copy: 12828.7019 0.0250 0.0249 0.0251
Scale: 12942.8860 0.0248 0.0247 0.0249
Add: 12910.1852 0.0374 0.0372 0.0377
Triad: 13030.0040 0.0369 0.0368 0.0372
I did get one outlier at 4 CPUs. Could be a timing glitch.
4 processors:
Copy: 13332.7765 0.0302 0.0240 0.0360
Scale: 13332.7765 0.0262 0.0240 0.0320
Add: 13332.6220 0.0400 0.0360 0.0480
Triad: 14999.0756 0.0391 0.0320 0.0480
Your timer does look dramatically less accurate than mine. The granularity
of yours looks to be around 0.0040. Where mine is 0.0001 or so. My
runs were pretty consistent. Notice that many of my min, max, and averages
are the same.
_______________________________________________
Beowulf mailing list, Beowulf@beowulf.org
To change your subscription (digest mode or unsubscribe) visit
http://www.beowulf.org/mailman/listinfo/beowulf
