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GNU GCC Vs Sun's Compiler on a SPARC
JigSaw writes "When doing research for his evaluation of Solaris 9 on his Ultra 5, Tony Bourke kept running into the same comment online over and over again: Sun's C compiler produces much faster code than GCC does. However, he couldn't find one set of benchmarks to back this up and so he did his own."
It's the same guy who bought a Sun system on ebay and has been writing columns on shiny new (to him anyway) system. The specs from the purchase article:
The system I'm using is a second generation of the Ultra 5, released in late 1998. Here are the specs:
System: Sun Ultra 5
Processor: UltraSPARC IIi 333 MHz, 2MB cache
Memory: 256 MB
HD: Seagate Medalist 7200 RPM IDE Pro 9140 8.4 GB
IDE Controller: Built-in UDMA2, 33 MB/s max
CD-ROM: 32x IDE
Video Controller: Sun PGX24 (ATI Mach64), 4 MB VRAM
Network: Built-in 10/100 NIC (hme, "Happy Meal" interface)
My knowledge of sun processors is a little lacking in the UltraSPARC II range, so I'll leave it to you to evaluate this one, My only exposure is the dead server CPU module for a paperweight. It and a foxtrot on the corkborad are my own version of the geek purity test.
Degaussing scares the bad magnetism out of the monitor and fills it with good karma.
To me this was the most interesting line of the article:
Sun's compiler was the clear winner. Surprisingly, the older version of GNU's GCC beat 3.3.2 by a very slim margin.
One of my favorite version numbers (2.95.3) is still getting good press. Cool.
dtg
The truth is an offense, but not a sin.------R. N. Marley
See Tony Bourke's older article, which conluded that 64 bit binaries are slower than 32 bit binaries. This set of statistics he posted has totally obliterated his previous conclusion. He had only used GCC 3.3.2 and assumed that compiling for both 32 and 64 bits were optimized similarly. However, in most of the benchmarks he did with Sun's compiler, 64 bit programs came ahead of 32 bit ones. This means that GCC 3.3.2 is not as well optimized for his computer for 64 bits as for 32 bits, while the Sun compiler is. If he had just looked at his own data, he would have seen that.
So, the benchmarks show maybe a 10-15% difference in favor of Sun's compiler. Does that Sun's compiler a "clear winner"? I think not.
First of all, it's far from clear that those differences are real. You can get much bigger differences from just changes in caching behavior, even with the same compiler.
Then, there is the question of whether Sun's compiler is actually correct. A lot of commercial compilers intentionally skirt or break the letter of the ANSI standards once you start enabling optimizations. GNU C/C++ is usually more careful.
Finally, you have to ask whether it matters. So, Sun's overpriced machines using their overpriced compilers run a bit faster than their overpriced machines using a free compiler. So what? If you want bang for the buck, or even just maximum bang, why in the world would you buy a Sun these days anyway?
Those may have been Stallman's original goals, but not necessarily of gcc anymore. Remember that the maintainers of gcc now aren't the original Stallman lead, FSF gcc folks, but of the splinter egcs group that forked gcc because they were extremely frustrated with the progress of gcc under the FSF. Once it became evident that egcs was making progress leaps and bounds past the FSF gcc, (to Stallman's credit) work on FSF gcc was dropped, and the egcs gcc became the official gcc.
People think that "The Cathedral and the Bazaar" was made in comparison between commercial and non-commercial programming models. It actually was modeled on FSF gcc (the Cathedral) and Linux kernel (the Bazaar) development. Eventually, at least in gcc development, the Bazaar won.
Add to this that compiler gets better with each release and I think it will soon be what Linux is for UNIX - making the rest obsolete.
I was talking to some Novell engineers at Linux World. They all love watcom. The watcom toolchain is being ported to linux. It already self bootstraps. Novell owns SuSE. I expect SuSE will be making use of watcom for linux in the future. All my projects are going to use Watcom from now on. I'm sick of the annoying voo-doo neccessary to make a cross compiler between unix and mingw/cygwin/djgpp using gcc. Watcom lets me cross compile out of the box. Granted the IDE needs some work, but wmake very powerful, though unique. All the basic unix userland you expect for a makefile (cp, rm, install) is a builtin command and calls to the tool chain (compiler, linker etc) are loaded as DLLs saving system calls, thus improving performance.
GCC is very mature, popular and supported, but its not going to be the only kid on the block for long now that Watcom is open source.
--- Justin Dearing http://www.justaprogrammer.net/ We're just programmers.