Red Flag announces an Intel-compiled distribution [LWN.net]

Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 14:44 UTC (Wed) by pontus (guest, #3701)
In reply to: Red Flag announces an Intel-compiled distribution by pglennon
Parent article: Red Flag announces an Intel-compiled distribution

Do you have any pointers to benchmarks? I keep seeing proprietary compilers advertised as generating ~ 20% faster code than GCC, but in the instance I managed to look up (Green Hills), the comparison was way old, from before the GCC 3.x release. In my experience, 3.x is significantly better than 2.95.

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Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 14:59 UTC (Wed) by pglennon (guest, #649) [Link] (2 responses)

No, as I said, I try to remain unburdened by facts when I make pronouncments. I do recall that the benchmarks I saw were against 2.95, and that the theory was that the intel compilers made heavy heavy use of the P3 and aboves SSE registers ( floating point computations? anyone? ).

not sure if gcc 3.0 delves more into the SSE realm or not, but I remember that 2.95 largely did not.

Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 15:33 UTC (Wed) by ca9mbu (guest, #11098) [Link] (1 responses)

Richard Guenther is actively tracking performance regressions on mainline and the lno branch. See http://www.tat.physik.uni-tuebingen.de/~rguenth/gcc/mon[...] for details. This means that at least performance won't get worse than it is currently - well, at least not without the gcc hackers knowing about it quickly anyway :) As for recent ICC vs. GCC benchmarks, the most recent I could find was http://gcc.gnu.org/ml/gcc/2004-04/msg00913.html.

Cheers,

Matt.

Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 15:37 UTC (Wed) by ca9mbu (guest, #11098) [Link]

Sorry folks - even after previewing that last comment I managed to screw it up! That last benchmark I found was to do with compilation time, not for the performance of the resulting binaries. Both are of course important, but the latter is arguably more important/more noticeable to end users.

Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 15:11 UTC (Wed) by B.Tegge (subscriber, #5720) [Link] (4 responses)

German magazine c't published some comparisons using SPEC for x86-64 systems a couple of months ago. IIRC Intel C 8.1 still came out first compared to GCC 3.4, however I don't remember any specifics. If you're interested I'll look them up tonight. Older results (using icc 8.0 and gcc 3.3) are published here: http://www.heise.de/ct/Redaktion/as/spec/ct0404160/

Red Flag announces an Intel-compiled distribution

Posted Aug 4, 2004 15:32 UTC (Wed) by pontus (guest, #3701) [Link] (3 responses)

Thanks, very useful. It seems that the intel compiler is 10-15% faster than GCC in specint after all.

Red Flag announces an Intel-compiled distribution

Posted Aug 5, 2004 2:49 UTC (Thu) by djabsolut (guest, #12799) [Link] (1 responses)

I wonder how often this 10-15% speed increase would show up in real life situations. e.g. how often does one encode three MPEG2 videos and at the same time write a 1000 page report and view a webpage with 100 java applets? The only time this speed increase would approach significantness is when one constantly uses heavy number-crunching (e.g. scientific programs, like Folding@Home). For other applications, is this 10-15% speed gain worth the loss of freedom?

Red Flag announces an Intel-compiled distribution

Posted Aug 5, 2004 18:36 UTC (Thu) by neoprene (guest, #8520) [Link]

"I wonder how often this 10-15% speed increase would show up in real life situations. e.g. how often does one encode three MPEG2.... "

Running the kernel at 100% for hours and hours I often do while using dvd::rip/transcode or running the game AA.

Right, many desktop users have no need for a processor over 1GHz for their e-mail, web sufing and word-processing, but a great many are pushing the hardware to its limits, and upgrade often. A 15% increase in processor GHz can more than double the CPU-price, so its not insignificant. [check a P4 or Athlon64 at 3GHz and price out the 15% increase].

A 15% increase in frame-rate in AA and Transcode translates into a better game experience and quicker production times in transcode [while the machine is useless for anything else]. The game AA is more CPU than GPU bounded. Turning off all detail in textures and reducing screen rez does exactly nothing to FPS. [Running the K7 kernel helps increase the minimum frame-rate, perhaps due to 3D-Now and similar optimisations].

A faster compiled solution for these applications would be most welcome.

Red Flag announces an Intel-compiled distribution

Posted Aug 5, 2004 4:12 UTC (Thu) by JoeBuck (subscriber, #2330) [Link]

Intel tunes their compiler to do well on benchmarks, the GCC team does not. What this means is that, while there are definitely codes where Intel's compiler beats GCC by a good deal, you should not expect to see as much improvement in your own codes as the SPEC tests would suggest.