Messages in this thread | | | From | Frank Kingswood <> | Subject | Re: [RFT] Please test rdtsc on various x86-64 hardware (app included) | Date | Tue, 19 Apr 2011 09:10:38 +0100 |
| |
On 18/04/11 20:32, Andrew Lutomirski wrote: > Hi all- > > I'd appreciate some help testing rdtsc's ordering wrt memory on > various hardware. You can download evil-clock-test code at: > > https://gitorious.org/linux-test-utils/linux-clock-tests/blobs/raw/master/evil-clock-test.cc
A low power core2 server:
CPU vendor : GenuineIntel CPU model : Intel(R) Core(TM)2 Duo CPU T8100 @ 2.10GHz CPU stepping : 6 TSC flags : tsc constant_tsc Using lfence_rdtsc because you have an Intel CPU Will test the "lfence;rdtsc" clock. Now test passed : margin 84 with 39213496 samples Load3 test passed: margin 20947164 with 15 samples Load test passed : margin 52 with 12466437 samples Store test failed as expected: worst error 1397 with 11151528 samples
That margin number seemed a bit high, rerunning gives:
CPU vendor : GenuineIntel CPU model : Intel(R) Core(TM)2 Duo CPU T8100 @ 2.10GHz CPU stepping : 6 TSC flags : tsc constant_tsc Using lfence_rdtsc because you have an Intel CPU Will test the "lfence;rdtsc" clock. Now test passed : margin 84 with 39201440 samples Load3 test passed: margin 7991 with 15 samples Load test passed : margin 52 with 12482714 samples Store test failed as expected: worst error 2457 with 11129294 samples
Frank
| |