My new laptop: Linux 64-bit vs Windows 32-bit using 2.2B SSSE3 app

================ LINUX =============
CPU time 7240.77652

<core_client_version>5.8.16</core_client_version>
Optimized SETI@Home Enhanced application
Optimizers: Ben Herndon, Josef Segur, Alex Kan, Simon Zadra
Linux port: Crunch3r, Hans Dorn, Simon Zadra
Version: Linux 64-bit based on S@H V5.15 'Noo? No - Ni!'
Revision: R-2.2B|xT|FFT:IPP_SSSE3|Ben-Joe
CPUID: Intel(R) Core(TM)2 CPU T5300 @ 1.73GHz
CPUs: 1, cores: 1, cache: L1=32K, L2=2048K, L3=0K
Features: MMX SSE SSE2 SSE3 SSSE3 x86_64
Speed: 1729 MHz

Work Unit Info
True angle range: 0.425850

Spikes Pulses Triplets Gaussians Flops
0 1 6 1 16109414470855

================ WINDOWS =============
CPU time 7213.595441

<core_client_version>5.10.12</core_client_version>
Optimized SETI@Home Enhanced application
Optimizers: Ben Herndon, Josef Segur, Alex Kan, Simon Zadra
Version: Windows SSE3-Core 2 32-bit based on S@H V5.15 'Noo? No - Ni!'
Revision: R-2.2B|xT|FFT:IPP_SSE3|Ben-Joe
CPUID: Intel Core 2 Duo 'Conroe 2M'
CPUs: 1, cores: 2, threads: 1 cache: L1=32K, L2=2048K, L3=0K
Features: MMX, SSE, SSE2, SSE3, SSSE3
speed: 1729 MHz -- read MB/s: L1=6452, L2=5583, RAM=3286

Work Unit Info
True angle range: 0.426468
Restarted at 21.57 percent.

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0 0 0 1 16094383483838

Quote from: michael37 on 07 Jul 2007, 11:36:00 pm

To my disappointment, Linux 64-bit is not faster than Windows 32-bit.

There are a couple of things one should keep in mind when making comparisons:

The WUs you were comparing were similar but not identical. It is expected to see run-time difference of a couple of percent when running similar WUs by same executable and on same hardware. The time difference you observed is negligible from this point of view.
All applications by Chicken soup are highly optimized for a given platform.
Let's compare 32-bit and 64-bit capabilities of your computer:

If running 64-bit application, it will use 64-bit pointers and 64-bit integers instead of 32-bit counterparts. If application only needs less than 2GB memory and does integer arithmetics on numbers that are less than approximately 2*10^9 (two billion), then using 64 bits will slow down the app.
If an application uses many registers, it'll benefit from 64-bit environment as there are more general-use registers available in that mode. Gain will be negligible to considerable, depending on how heavy registers are in use.
If an application uses floating-point arithmetics, then it really doesn't matter as FP part of processor is not changed in any way.
If an application uses any of SS(S)E instructions, it'll be roughly the same. Most of SS(S) extensions are bitness-agnostic.
The real benefit from using 64-bit platform in Linux comes from the fact, that default GCC configuration has been changed from using 387 (FPU) floating-point arithmetics to using SSE arithmetics. This could have been done earlier, but it really is safe to do so on 64-bit platform since there aren't any x86_64 processors (neither Intel nor AMD) that don't support at least SSE2 instructions.

As I wrote before: all Chicken apps are highly optimized (that is, they use instructions as advanced as possible for any given CPU) and you can't really expect to have 64-bit apps faster just because they are 64-bit.

What is most remarkable about Chicken apps is the fact, that Linux apps are generally (at least) as fast as Windows counterparts. This didn't use to be the fact until Chicken and the flock started to do their marvelous work. Kudos to all of them.

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