From 7e9363b050a0eb593e83c16a288a4b08664b93ce Mon Sep 17 00:00:00 2001 From: Megan Wachs Date: Wed, 1 Mar 2017 12:12:05 -0800 Subject: Add a 'performance counters' demo. --- software/performance_counters/Makefile | 6 ++ .../performance_counters/performance_counters.c | 111 +++++++++++++++++++++ 2 files changed, 117 insertions(+) create mode 100644 software/performance_counters/Makefile create mode 100644 software/performance_counters/performance_counters.c (limited to 'software') diff --git a/software/performance_counters/Makefile b/software/performance_counters/Makefile new file mode 100644 index 0000000..eb3e8f1 --- /dev/null +++ b/software/performance_counters/Makefile @@ -0,0 +1,6 @@ +TARGET = performance_counters +C_SRCS += performance_counters.c +CFLAGS += -O2 -fno-builtin-printf + +BSP_BASE = ../../bsp +include $(BSP_BASE)/env/common.mk diff --git a/software/performance_counters/performance_counters.c b/software/performance_counters/performance_counters.c new file mode 100644 index 0000000..e7c12a3 --- /dev/null +++ b/software/performance_counters/performance_counters.c @@ -0,0 +1,111 @@ +// See LICENSE for license details. + +// This demo shows how to use basic +// RISC-V profiling counters, mcycle +// (counts the number of processor cycles) +// and minstret (counts the number of retired instructions). +// Note that both are writable as well. + +#include + +// The CSR encodings are in this header. +#include "encoding.h" + +// The mcycle counter is 64-bit counter, but since +// Freedom E platforms use RV32, we must access it as +// 2 32-bit registers. At 256MHz, the lower bits will +// roll over approx. every 5 seconds, so we check for +// rollover with this routine as suggested by the +// RISC-V Priviledged Architecture Specification. + +#define rdmcycle(x) { \ + uint32_t lo, hi, hi2; \ + __asm__ __volatile__ ("1:\n\t" \ + "csrr %0, mcycleh\n\t" \ + "csrr %1, mcycle\n\t" \ + "csrr %2, mcycleh\n\t" \ + "bne %0, %2, 1b\n\t" \ + : "=r" (hi), "=r" (lo), "=r" (hi2)) ; \ + *(x) = lo | ((uint64_t) hi << 32); \ + } + + +// The minstret counter is 64-bit counter, but +// Freedom E platforms use RV32, we must access it as +// 2 32-bit registers, same as for mcycle. + +#define rdminstret(x) { \ + uint32_t lo, hi, hi2; \ + __asm__ __volatile__ ("1:\n\t" \ + "csrr %0, minstreth\n\t" \ + "csrr %1, minstret\n\t" \ + "csrr %2, minstreth\n\t" \ + "bne %0, %2, 1b\n\t" \ + : "=r" (hi), "=r" (lo), "=r" (hi2)) ; \ + *(x) = lo | ((uint64_t) hi << 32); \ + } + +// Simple program to measure the performance of. + +int factorial(int i){ + + int result = 1; + for (int ii = 1; ii <= i; ii++) { + result = result * i; + } + + return result; + +} + + +int main() +{ + + uint64_t before_cycle; + uint64_t before_instret; + + uint64_t after_cycle; + uint64_t after_instret; + + printf("\n\nDemo 1: Using Counter Differences.\n"); + + for (int ii = 0; ii < 3; ii++){ + rdmcycle(&before_cycle); + rdminstret(&before_instret); + + volatile int result = factorial (100); + + rdmcycle(&after_cycle); + rdminstret(&after_instret); + + printf("Loop %d: Retired %d instructions in %d cycles\n", + ii, + (uint32_t)(after_instret - before_instret), + (uint32_t)(after_cycle - before_cycle)); + } + + printf("\n\nDemo 2: Clearing Counters, Using Values Directly.\n"); + + for (int ii = 0; ii < 3; ii++){ + + write_csr(mcycle, 0); + write_csr(mcycleh, 0); + write_csr(minstret, 0); + write_csr(minstreth, 0); + + volatile int result = factorial (100); + + rdmcycle(&after_cycle); + rdminstret(&after_instret); + + printf("Loop %d: Retired %d instructions in %d cycles\n", + ii, + (uint32_t)(after_instret), + (uint32_t)(after_cycle)); + + } + + return 0; + +} -- cgit v1.2.3 From 1f7bd8343e01e9e17007ec05353b394e8157dfea Mon Sep 17 00:00:00 2001 From: Megan Wachs Date: Wed, 1 Mar 2017 12:12:54 -0800 Subject: led_fade: Add NO_INIT flag to keep default clock frequency and UART configurations. --- software/led_fade/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'software') diff --git a/software/led_fade/Makefile b/software/led_fade/Makefile index c42049b..bbdba66 100644 --- a/software/led_fade/Makefile +++ b/software/led_fade/Makefile @@ -1,6 +1,6 @@ TARGET = led_fade C_SRCS += led_fade.c -CFLAGS += -O2 -fno-builtin-printf +CFLAGS += -O2 -fno-builtin-printf -DNO_INIT BSP_BASE = ../../bsp include $(BSP_BASE)/env/common.mk -- cgit v1.2.3