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From: Charles Grassl (cmg@magnet.cray.com)
Date: Wed Nov 13 1991 - 13:07:30 CST


Hello John;

I'm still trying to figure out how the CM-2 gets 80,000 Mbyte/sec. I
suspect that the compiler has "optimized away" dead code. Most current
compilers compilers should be able to delete some dead code is a test
program such as yours.

Below are results for 1, 2, 4, 8 and 16 CPUs on a CRAY Y-MP C90.
Hope that you can soon include these in your table.

Regards,

-- 
Charles M. Grassl
Cray Research, Inc.
(612) 683-3531 cmg@cray.com

1 CPU -------------------------------------- Single precision appears to have 14 digits of accuracy Assuming 8 bytes per default REAL word -------------------------------------- Timing calibration ; time = 11.02508232 hundredths of a second Increase the size of the arrays if this is <30 and your clock precision is =<1/100 second --------------------------------------------------- Function Rate (MB/s) RMS time Min time Max time Assignment: 6965.4395 0.0368 0.0368 0.0368 Scaling : 6965.3798 0.0368 0.0368 0.0368 Summing : 9378.7332 0.0411 0.0409 0.0413 SAXPYing : 9500.7178 0.0404 0.0404 0.0404

2 CPUs -------------------------------------- Single precision appears to have 14 digits of accuracy Assuming 8 bytes per default REAL word -------------------------------------- Timing calibration ; time = 5.51878446 hundredths of a second Increase the size of the arrays if this is <30 and your clock precision is =<1/100 second --------------------------------------------------- Function Rate (MB/s) RMS time Min time Max time Assignment: 13865.9708 0.0185 0.0185 0.0185 Scaling : 13905.4840 0.0184 0.0184 0.0184 Summing : 18233.2027 0.0211 0.0211 0.0211 SAXPYing : 18246.2586 0.0211 0.0210 0.0211

4 CPUs -------------------------------------- Single precision appears to have 14 digits of accuracy Assuming 8 bytes per default REAL word -------------------------------------- Timing calibration ; time = 2.76657822 hundredths of a second Increase the size of the arrays if this is <30 and your clock precision is =<1/100 second --------------------------------------------------- Function Rate (MB/s) RMS time Min time Max time Assignment: 27610.2594 0.0093 0.0093 0.0093 Scaling : 27789.5522 0.0092 0.0092 0.0092 Summing : 34633.3071 0.0111 0.0111 0.0112 SAXPYing : 35044.1485 0.0110 0.0110 0.0110

8 CPUs -------------------------------------- Single precision appears to have 14 digits of accuracy Assuming 8 bytes per default REAL word -------------------------------------- Timing calibration ; time = 1.4161938 hundredths of a second Increase the size of the arrays if this is <30 and your clock precision is =<1/100 second --------------------------------------------------- Function Rate (MB/s) RMS time Min time Max time Assignment: 55071.9123 0.0047 0.0046 0.0048 Scaling : 55391.7676 0.0046 0.0046 0.0047 Summing : 60843.3497 0.0063 0.0063 0.0064 SAXPYing : 63229.5729 0.0061 0.0061 0.0063

16 CPUs -------------------------------------- Single precision appears to have 14 digits of accuracy Assuming 8 bytes per default REAL word -------------------------------------- Timing calibration ; time = 0.82603542 hundredths of a second Increase the size of the arrays if this is <30 and your clock precision is =<1/100 second --------------------------------------------------- Function Rate (MB/s) RMS time Min time Max time Assignment:105497.3864 0.0024 0.0024 0.0024 Scaling :104654.3724 0.0025 0.0024 0.0025 Summing :101736.0623 0.0038 0.0038 0.0038 SAXPYing :103812.8177 0.0037 0.0037 0.0038



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