The 2012 Kernel Summit
Posted Sep 11, 2012 3:20 UTC (Tue) by BenHutchings
In reply to: The 2012 Kernel Summit
Parent article: The 2012 Kernel Summit
Shows a 5-40% improvement or most applications.
I think I wasn't very clear. It is certainly possible to build significantly faster binaries for the RPi processor than are currently available in the armel architecture. But how much of the performance improvement is due to using the hard-float vs soft-float ABI and how much is due to optimising for v6 vs v4? You see, it should be possible to build optimised libraries for v6 processors and then use the dynamic linker's CPU feature checks to select between the v4-compatible and optimised v6 builds (like we do on i386 for libraries that benefit from use of CMOV and SSE2). And those could be added to Debian without any need to fork or rebuild. Has that been tried and compared?
A more "fair" set of armv7 vs armv7 benchmarks showing up to 1400% improvement, though indeed most applications are within the margin of error. The most interesting gains are IMHO in the ffmpeg and gtk benchmarks.
I can't help wondering whether the huge gains for two POVray tests (not seen in the Phoronix benchmarks that use POVray) are due to some mistake in building them (e.g. building without using the FPU at all). Also tests on a v7 core aren't necessarily representative of the RPi's v6 core. But this is hopefully somewhat indicative of the difference between hard-float and soft-float, and the results really are quite mixed!
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