[LLVMdev] [llvm-testresults] bwilson__llvm-gcc_PROD__i386 nightly tester results

Rotem, Nadav nadav.rotem at intel.com
Mon Jul 25 10:11:04 PDT 2011


Did you disable hyper-threading and Turbo ? Turbo alone can boost/hinder the performance of kernels by 30%, and make the perf results very unstable.


-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu] On Behalf Of Duncan Sands
Sent: Monday, July 25, 2011 18:11
To: Bob Wilson
Cc: llvm-testresults at cs.uiuc.edu; LLVMdev
Subject: Re: [LLVMdev] [llvm-testresults] bwilson__llvm-gcc_PROD__i386 nightly tester results

Hi Bob,

>> A big compile time regression.  Any ideas?
>> Ciao, Duncan.
> False alarm.  For some reason that I have not yet been able to figure out, these tests run significantly more slowly when I run them during the daytime, which I did for that run.  I checked a few of the worst regressions reported here and they all recovered in subsequent runs.

here is a crazy idea: during the day the room the computer is in is hotter,
and to avoid overheating the CPU frequency is reduced, resulting in the machine
running slower.

Ciao, Duncan.
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