From 0cf52e2f5bc1e5e7f243e45eecfe3060ffeda6f2 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Mon, 2 Aug 2021 14:19:33 +0200
Subject: [PATCH] make experiment size adjustable
---
bench.c | 16 ++++++++++------
common.h | 2 ++
paio-thrd.c | 4 ++++
3 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/bench.c b/bench.c
index 4199b1e..2a2494d 100644
--- a/bench.c
+++ b/bench.c
@@ -12,8 +12,8 @@
void init(int fd);
void do_write(int fd, const void *buf, size_t count);
-const size_t warmup = 10000;
-const size_t iterations = 1000000;
+size_t warmup = 10000;
+size_t iterations = 1000000;
#define BUFSIZE 64
@@ -44,10 +44,14 @@ int main() {
int fd = create_eventfd();
init(fd);
+ const size_t exp_warmup = warmup;
+ const size_t exp_iterations = iterations;
- for (size_t i = 0; i < warmup; ++i) do_write(fd, &write_buf, sizeof(write_buf));
+ if (exp_iterations == 0) errx(EXIT_FAILURE, "experiment must do at least one iteration");
- for (int64_t i = 1; i <= iterations; ++i) {
+ for (size_t i = 0; i < exp_warmup; ++i) do_write(fd, &write_buf, sizeof(write_buf));
+
+ for (int64_t i = 1; i <= exp_iterations; ++i) {
do_write(fd, &write_buf, sizeof(write_buf));
if (__builtin_add_overflow(nanos_sum, clock_diff_nanos(), &nanos_sum))
errx(EXIT_FAILURE, "nanos overflowed at %ld", i);
@@ -58,8 +62,8 @@ int main() {
// Since uint64_t <-> double conversion are not well defined
// and we use really small units (cycles and nanoseconds) I am willing
// to accept that we throw away anything after the decimal point.
- uint64_t avg_nanos = nanos_sum / iterations;
- uint64_t avg_cycles = cycles_sum / iterations;
+ uint64_t avg_nanos = nanos_sum / exp_iterations;
+ uint64_t avg_cycles = cycles_sum / exp_iterations;
printf("%lu ns, %lu cycles\n", avg_nanos, avg_cycles);
return 0;
diff --git a/common.h b/common.h
index b8acbfd..80360f2 100644
--- a/common.h
+++ b/common.h
@@ -1,3 +1,5 @@
#pragma once
#define unlikely(x) __builtin_expect(!!(x), 0)
+
+extern size_t warmup, iterations;
diff --git a/paio-thrd.c b/paio-thrd.c
index ef7c365..f2809af 100644
--- a/paio-thrd.c
+++ b/paio-thrd.c
@@ -5,6 +5,7 @@
#include <stdint.h>
#include <stdlib.h>
+#include "common.h"
#include "stopwatch.h"
atomic_int done;
@@ -19,6 +20,9 @@ void callback(union sigval sigval) {
}
void init(int fd) {
+ // decrease the experiment size because this takes much longer than anything else
+ warmup = 10;
+ iterations = 100;
aiocb.aio_fildes = fd;
aiocb.aio_sigevent.sigev_notify = SIGEV_THREAD;
aiocb.aio_sigevent.sigev_notify_function = callback;
--
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