I gave a short presentation on LLVM for a couple of
people here, and they had questions I could not immediately
answer. The questions are rather obvious, so I'm hoping that
someone has already found out the answers. So here we go:
1) What is the relative size of LLVM bitcode files and the
corresponding native binaries? Are there significant
differences between targets (e.g. x86, ARM, Thumb,...)
2) What is the relative performance of code generated by LLVM
and gcc respectively?
I am not looking for exact answers, rough ballpark figures
are quite sufficient.
--
Pertti
On May 12, 2008, at 2:59 AM, Pertti Kellomäki wrote:> 2) What is the relative performance of code generated by LLVM > and gcc respectively?See llvm.org/nightlytest Many testers run various benchmarks and produces comparison numbers daily.> I am not looking for exact answers, rough ballpark figures > are quite sufficient.- Devang
Am Montag, den 12.05.2008, 09:08 -0700 schrieb Devang Patel:> On May 12, 2008, at 2:59 AM, Pertti Kellomäki wrote: > > > 2) What is the relative performance of code generated by LLVM > > and gcc respectively? > > See llvm.org/nightlytestWhich does not compare GCC vs. LLVM. (I haven't seen this announced as the nightly tester's purpose either.)> Many testers4 machines with a total of 15 comparisons have been reporting on a regular basis. Sorry, but this is far from "many".> run various benchmarks and > produces comparison numbers daily.Regards, Jo
Devang Patel wrote:> See llvm.org/nightlytestThanks, that is exactly the kind of information I was looking for. -- Pertti
> See llvm.org/nightlytest Many testers run various benchmarks > and produces comparison numbers daily.Can I trust those numbers? For example, right now I'm looking at http://llvm.org/nightlytest/machine.php?machine=230. "CVS checkout time" might be wrong, as LLVM is now in SVN. This column also jitters heavily. However, it's not really important. "Configure time CPU": is always 0, which must be a blantant lie :-) "Build time CPU" is usually higher than "Build time wall". Isn't wall=cpu+system, so do we have negative system times here? I could be completely wrong, but this looks strange. However, for the Dejagnu test, it hold's that CPU time < wall time. Now I look at Chris' PPC box: http://llvm.org/nightlytest/machine.php?machine=153. And here suddenly "Dejagnu CPU time" > "Dejagnu wall time". Now I'm confused.