GCC vs. LLVM-GCC Benchmarks

[EnderWiggin]

When building these tests, is there a way to also build and affect the C runtime library. While I can appreciate that many of these tests have "hard stuff" in their code, the performance of an app is always so dependent on the performance of it's underlying runtime library (for things like memcpy, strcmp, etc.) that I think it's worth a look.

[kraftman]

The way timed compilation tests are written in PTS gcc should take full advantage of the available cores.

For example the apache compile test:

\$TIMER_START
make -s -j \$NUM_CPU_JOBS 2>&1
\$TIMER_STOP" > time-compile-apache

Yes, I just looked at this

[deanjo]

But do normal users really care?

I think compile times should only be used as a test workload when comparing computers; using compile times to benchmark compilers is useless to most people (99%? more?).

Probably not, but for the most part 99% of users don't care about the delta difference on most of the benchmarks. If it runs, that's good enough for them. The exception being maybe the game benches where even then once your maxing out your monitor's capability everything else is purely for bragging rights.

[deanjo]

Someone mentioned there could be only one core used when comes to GCC and Ubuntu vs OS X benchmarks. Btw. I heard GCC is optimized to be good at some benchmarks, but I wonder if its better results have reflection in reality.

The way timed compilation tests are written in PTS gcc should take full advantage of the available cores.

For example the apache compile test:

\$TIMER_START
make -s -j \$NUM_CPU_JOBS 2>&1
\$TIMER_STOP" > time-compile-apache

[[Knuckles]]

Couple of factors I would guess comes into play. LLVM is fairly young in development and the biggest improvements so far as performance concerning LLVM is the time to compile. Unfortunately we haven't seen any of those compile times in the tests.

But do normal users really care?

I think compile times should only be used as a test workload when comparing computers; using compile times to benchmark compilers is useless to most people (99%? more?).

[srg_13]

I've been playing with Clang, and it really is very cool. Compile times are a lot better than GCC, and error messages are far more clear. I'm really glad Apple are funding development for it!

[kraftman]

Couple of factors I would guess comes into play. LLVM is fairly young in development and the biggest improvements so far as performance concerning LLVM is the time to compile. Unfortunately we haven't seen any of those compile times in the tests.

Someone mentioned there could be only one core used when comes to GCC and Ubuntu vs OS X benchmarks. Btw. I heard GCC is optimized to be good at some benchmarks, but I wonder if its better results have reflection in reality.

[Rip-Rip]

Hum, LLVM-GCC combines GCC frontend with LLVM backend (optimizer and code generator).

Thanks, I've edited (in fact, I wanted to write frontend...).

[tettamanti]

Plus you won't see any speed advantage because phoronix is using the gcc backend.

Hum, LLVM-GCC combines GCC frontend with LLVM backend (optimizer and code generator).

[tettamanti]

next up we will be testing LLVM/Clang to see how that performs.

Shouldn't make any difference, Clang is just the frontend, right?