Benchmark for barycentric formula

src/poly_barycentric_bench.c

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+/*
+ * Copyright 2021 Benjamin Edgington
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h> // malloc(), free(), atoi()
+#include <stdio.h>  // printf()
+#include <assert.h> // assert()
+#include <unistd.h> // EXIT_SUCCESS/FAILURE
+#include "bench_util.h"
+#include "test_util.h"
+#include "c_kzg.h"
+
+// Run the benchmark for `max_seconds` and return the time per iteration in nanoseconds.
+long run_bench(int scale, int max_seconds) {
+    timespec_t t0, t1;
+    unsigned long total_time = 0, nits = 0;
+
+    uint64_t width = (uint64_t)1 << scale;
+
+    FFTSettings fs;
+
+    new_fft_settings(&fs, scale);
+
+    poly_l p;
+    fr_t x, y;
+    new_poly_l(&p, width);
+
+    for (int i = 0; i < width; i++) {
+        p.values[i] = rand_fr();
+    }
+    x = rand_fr();
+
+    while (total_time < max_seconds * NANO) {
+        clock_gettime(CLOCK_REALTIME, &t0);
+
+        eval_poly_l(&y, &p, &x, &fs);
+
+        clock_gettime(CLOCK_REALTIME, &t1);
+        nits++;
+        total_time += tdiff(t0, t1);
+    }
+
+    free_poly_l(&p);
+    free_fft_settings(&fs);
+
+    return total_time / nits;
+}
+
+int main(int argc, char *argv[]) {
+    int nsec = 0;
+
+    switch (argc) {
+    case 1:
+        nsec = NSEC;
+        break;
+    case 2:
+        nsec = atoi(argv[1]);
+        break;
+    default:
+        break;
+    };
+
+    if (nsec == 0) {
+        printf("Usage: %s [test time in seconds > 0]\n", argv[0]);
+        exit(EXIT_FAILURE);
+    }
+
+    printf("*** Benchmarking Barycentric Formula (eval_poly_l), %d second%s per test.\n", nsec, nsec == 1 ? "" : "s");
+    for (int scale = 6; scale <= 15; scale++) {
+        printf("eval_poly_l/scale_%d %lu ns/op\n", scale, run_bench(scale, nsec));
+    }
+
+    return EXIT_SUCCESS;
+}