Replies to post #41808 on Advanced Micro Devices Inc (AMD)

[upc]

What Anand's "primegen" was actually measuring:

*locking* and *unlocking* of the thread-safe version of putchar() was the bottleneck.

switching to unlocked putchar made the benchmark run twice as fast.

commenting out the putchar stuff entirely resulted in another factor of 2 faster.

So:

50% of time involves locking.
25% of time involved input/output
25% of time was actually doing arithmetic, calculating primes.


Gosh, I wonder if The Prescott New Instructions MONITOR and MWAIT have anything to do with the selection of this benchmark, and the performance of Nocona?

http://www.aceshardware.com/forum?read=115093892

upc