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Small mlucas issue on non-x86
I thought I might as well see just how slowly mlucas runs on a last-year's ARM.
The current downloadable tarfile of mlucas (Mlucas_10.09.2011; I appreciate this is old, is there a newer place to look?) doesn't build unless USE_SSE2 is defined, because the section around lines 1441 to 1458 of radix16_ditN_cy_dif1.c (only) uses *bjmodn0 which is incorrect if !USE_SSE2 I did #if !defined(USE_SSE2) #define BJSTAR #else #define BJSTAR * #endif then replaced *bjmodn0 with BJSTAR modn0 but I appreciate that makes the code a bit ugly. It's really not terribly fast: [code] M2614999: using FFT length 128K = 131072 8-byte floats. this gives an average 19.950859069824219 bits per digit Using complex FFT radices 8 16 32 16 1000 iterations of M2614999 with FFT length 131072 = 128 K Res64: 1A184504D2DE2D3C. AvgMaxErr = 0.000000000. MaxErr = 0.000000000. Program: E3.0x Res mod 2^36 = 20717645116 Res mod 2^35 - 1 = 5934292942 Res mod 2^36 - 1 = 4090378120 Clocks = 00:00:45.939 M42643801: using FFT length 2304K = 2359296 8-byte floats. this gives an average 18.074799007839626 bits per digit Using complex FFT radices 9 8 8 8 16 16 10 iterations of M42643801 with FFT length 2359296 = 2304 K Res64: 9BDB491DF4C00002. AvgMaxErr N/A. MaxErr = 0.000000000. Program: E3.0x Res mod 2^36 = 59940798466 Res mod 2^35 - 1 = 11033316518 Res mod 2^36 - 1 = 15286304084 Clocks = 00:00:10.410 [/code] (for comparison, a 3.4GHz Sandy Bridge machine gave 0.045s/i for 42643801 and 0.0021s/i for 2614999; so about 22 times faster) I'm trying different compiler options; I tried enabling multi-threading but got a message saying that the sensitivity list for radix44 needed updating. Have you got a newer version of that? |
What is a last year ARM? :)
Also what compiler flags did you try and what gcc version do you use? |
ODROID-X, Exynos 4412 @ 1.4GHz (apparently, though /proc/cpuinfo says 2000 bogomips). Running Ubuntu 12.04.
So it's a Cortex-A9; you might reasonably argue that that is an October 2007 CPU, but the Exynos 4412 was only announced in April 2012, and I bought the board on 14 September 2012. I think I should get stuff working nicely on this board before contemplating an A15-based replacement. I compiled with gcc-4.6.2 -march=v7-a -mcpu=cortex-a9. Looking at the disassembly, it is using vfp instructions. It is slightly embarrassing given my current workplace, but even with an ARM ARM in front of me I can't work out whether this architecture has instructions that treat a 128-bit register as two doubles ... |
[QUOTE=fivemack;326337]ODROID-X, Exynos 4412 @ 1.4GHz (apparently, though /proc/cpuinfo says 2000 bogomips). Running Ubuntu 12.04.[/QUOTE]
I guess this means the board booted at 1 GHz. [QUOTE]So it's a Cortex-A9; I compiled with gcc-4.6.2 -march=v7-a -mcpu=cortex-a9. Looking at the disassembly, it is using vfp instructions.[/QUOTE]Can you check if it is passing function parameters in FP registers? I guess it should since IIRC Ubuntu is using the hard FP ABI. [QUOTE]It is slightly embarrassing given my current workplace, but even with an ARM ARM in front of me I can't work out whether this architecture has instructions that treat a 128-bit register as two doubles ...[/QUOTE]Heh, the ARM ARM is not easy to read :smile: ARMv7 doesn't have SIMD with doubles. ARMv8 does, but you'll have to wait for silicon to arrive... |
[QUOTE=fivemack;326212]I thought I might as well see just how slowly mlucas runs on a last-year's ARM.
The current downloadable tarfile of mlucas (Mlucas_10.09.2011; I appreciate this is old, is there a newer place to look?) doesn't build unless USE_SSE2 is defined, because the section around lines 1441 to 1458 of radix16_ditN_cy_dif1.c (only) uses *bjmodn0 which is incorrect if !USE_SSE2[/QUOTE] Hi, Tom: Send me your e-mail address and I'll be happy to provide you with the recent tarball being used by myself and the new-prime verifiers. It's high time for me to update the code at my ftp page, I suppose - would really like to get AVX support finished before spending time on release packaging, though. |
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