I got a Raspberry Pi 2 B (RPI2), and it’s a lot of fun. Gambit from Github runs out of the box with the compiler that’s shipped with Raspbian (the RPI version of Debian).

I was trying out some options to see how to best take advantage of the hardware. The numbers follow my sig.

Brad

I have a simple test:

cutie-pi:~/programs/gambit> gsi -v v4.7.4 20150228031125 armv7l-unknown-linux-gnueabihf "./configure 'CC=gcc -march=armv7-a -mfpu=vfpv4 -mhard-float' '--enable-single-host' '--enable-shared' '--enable-multiple-versions'" cutie-pi:~/programs/gambit> gsi -e '(define a (time (expt 3 1000000)))(define b (time (* a a)))' (time (expt 3 1000000)) 494 ms real time 490 ms cpu time (490 user, 0 system) 7 collections accounting for 8 ms real time (10 user, 0 system) 9166544 bytes allocated 2001 minor faults no major faults (time (* a a)) 522 ms real time 530 ms cpu time (520 user, 10 system) 2 collections accounting for 4 ms real time (10 user, 0 system) 8817880 bytes allocated 2067 minor faults no major faults

You can install gcc-4.8, but then it runs out of memory compiling _t-univ.c, so I reconfigured Gambit to not include _t-univ.*, and got the following results:

cutie-pi:~/programs/gambit> gsi -v v4.7.4 20150228031125 armv7l-unknown-linux-gnueabihf "./configure 'CC=gcc-4.8 -mcpu=cortex-a7 -mfpu=neon-vfpv4 -mfloat-abi=hard' '--enable-single-host' '--enable-shared' '--enable-multiple-versions'" cutie-pi:~/programs/gambit> gsi -e '(define a (time (expt 3 1000000)))(define b (time (* a a)))' (time (expt 3 1000000)) 430 ms real time 430 ms cpu time (420 user, 10 system) 7 collections accounting for 8 ms real time (10 user, 0 system) 9166544 bytes allocated 2001 minor faults no major faults (time (* a a)) 453 ms real time 450 ms cpu time (440 user, 10 system) 2 collections accounting for 3 ms real time (0 user, 0 system) 8817880 bytes allocated 2067 minor faults no major faults

And on an experiment in spectral identification that mainly does F64 inner products, I get with the default build

(time (run-experiment-and-graph 5)) 785617 ms real time 785590 ms cpu time (785040 user, 550 system) 33 collections accounting for 442 ms real time (350 user, 80 system) 3216061748 bytes allocated 30338 minor faults no major faults

and with the gcc-4.8 build I get

(time (run-experiment-and-graph 5))

(time (run-experiment-and-graph 5)) 739829 ms real time 739790 ms cpu time (739620 user, 170 system) 33 collections accounting for 292 ms real time (310 user, 0 system) 3216060588 bytes allocated 17663 minor faults no major faults

On my Intel Core i7 with

firefly:~> gsi -v v4.7.4 20150228031125 x86_64-unknown-linux-gnu "./configure '--enable-single-host' '--enable-shared' '--enable-multiple-versions’”

I get

firefly:~> gsi -e '(define a (time (expt 3 1000000)))(define b (time (* a a)))' (time (expt 3 1000000)) 19 ms real time 19 ms cpu time (19 user, 0 system) 2 collections accounting for 0 ms real time (0 user, 0 system) 9133952 bytes allocated 2154 minor faults no major faults (time (* a a)) 20 ms real time 20 ms cpu time (20 user, 0 system) 2 collections accounting for 0 ms real time (0 user, 0 system) 8817984 bytes allocated 1637 minor faults no major faults

and

(time (run-experiment-and-graph 5))

(time (run-experiment-and-graph 5)) 50700 ms real time 50709 ms cpu time (50630 user, 79 system) 39 collections accounting for 66 ms real time (60 user, 8 system) 3754964264 bytes allocated 74006 minor faults no major faults

I thought I should be able to get things to run faster on the RPI2, but I don’t know what the gcc options should be. Maybe 32-bit versus 64-bit is the big difference.

cat /proc/cpuinfo says

processor : 3 model name : ARMv7 Processor rev 5 (v7l) BogoMIPS : 38.40 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xc07 CPU revision : 5

Hardware : BCM2709 Revision : a21041 Serial : 00000000c222f2d2

and

processor : 7 vendor_id : GenuineIntel cpu family : 6 model : 60 model name : Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz stepping : 3 microcode : 0x7 cpu MHz : 3497.750 cache size : 8192 KB physical id : 0 siblings : 8 core id : 3 cpu cores : 4 apicid : 7 initial apicid : 7 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm bogomips : 6784.67 clflush size : 64 cache_alignment : 64 address sizes : 39 bits physical, 48 bits virtual power management: