bench/ioq: New ioq microbenchmark

2 files changed, 332 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index b0d6e46..8a7b270 100644
--- a/Makefile
+++ b/Makefile
@@ -45,7 +45,8 @@ BINS := \
     bin/tests/mksock \
     bin/tests/units \
     bin/tests/xspawnee \
-    bin/tests/xtouch
+    bin/tests/xtouch \
+    bin/bench/ioq
 
 all: ${BINS}
 .PHONY: all
@@ -215,6 +216,14 @@ ${DISTCHECKS}::
 	    && ${MAKE} check TEST_FLAGS="--sudo --verbose=skipped"
 	@test "$${GITHUB_ACTIONS-}" != true || printf '::endgroup::\n'
 
+## Benchmarks (`make bench`)
+
+bench: bin/bench/ioq
+.PHONY: bench
+
+bin/bench/ioq: obj/bench/ioq.o ${LIBBFS}
+OBJS += obj/bench/ioq.o
+
 ## Automatic dependency tracking
 
 # Rebuild when the configuration changes
diff --git a/bench/ioq.c b/bench/ioq.c
new file mode 100644
index 0000000..0886e9e
--- /dev/null
+++ b/bench/ioq.c
@@ -0,0 +1,322 @@
+// Copyright © Tavian Barnes <tavianator@tavianator.com>
+// SPDX-License-Identifier: 0BSD
+
+#include "atomic.h"
+#include "bfs.h"
+#include "bfstd.h"
+#include "diag.h"
+#include "ioq.h"
+#include "sighook.h"
+#include "xtime.h"
+
+#include <errno.h>
+#include <locale.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+/** Which clock to use for benchmarking. */
+static clockid_t clockid = CLOCK_REALTIME;
+
+/** Get a current time measurement. */
+static void gettime(struct timespec *tp) {
+	int ret = clock_gettime(clockid, tp);
+	bfs_everify(ret == 0, "clock_gettime(%d)", (int)clockid);
+}
+
+/**
+ * Time measurements.
+ */
+struct times {
+	/** The start time. */
+	struct timespec start;
+
+	/** Total requests started. */
+	size_t pushed;
+	/** Total requests finished. */
+	size_t popped;
+
+	/** Number of timed requests (latency). */
+	size_t timed_reqs;
+	/** The start time for the currently tracked request. */
+	struct timespec req_start;
+	/** Whether a timed request is currently in flight. */
+	bool timing;
+
+	/** Latency measurements. */
+	struct {
+		struct timespec min;
+		struct timespec max;
+		struct timespec sum;
+	} latency;
+};
+
+/** Initialize a timer. */
+static void times_init(struct times *times) {
+	*times = (struct times) {
+		.latency = {
+			.min = { .tv_sec = 1000 },
+		},
+	};
+	gettime(&times->start);
+}
+
+/** Start timing a single request. */
+static void start_request(struct times *times) {
+	gettime(&times->req_start);
+	times->timing = true;
+}
+
+/** Finish timing a request. */
+static void finish_request(struct times *times) {
+	struct timespec elapsed;
+	gettime(&elapsed);
+	timespec_sub(&elapsed, &times->req_start);
+
+	timespec_min(&times->latency.min, &elapsed);
+	timespec_max(&times->latency.max, &elapsed);
+	timespec_add(&times->latency.sum, &elapsed);
+
+	bfs_assert(times->timing);
+	times->timing = false;
+	++times->timed_reqs;
+}
+
+/** Add times to the totals, and reset the lap times. */
+static void times_lap(struct times *total, struct times *lap) {
+	total->pushed += lap->pushed;
+	total->popped += lap->popped;
+	total->timed_reqs += lap->timed_reqs;
+
+	timespec_min(&total->latency.min, &lap->latency.min);
+	timespec_max(&total->latency.max, &lap->latency.max);
+	timespec_add(&total->latency.sum, &lap->latency.sum);
+
+	times_init(lap);
+}
+
+/** Print some times. */
+static void times_print(const struct times *times, long seconds) {
+	struct timespec elapsed;
+	gettime(&elapsed);
+	timespec_sub(&elapsed, &times->start);
+
+	double fsec = timespec_ns(&elapsed) / 1.0e9;
+	double iops = times->popped / fsec;
+	double mean = timespec_ns(&times->latency.sum) / times->timed_reqs;
+	double min = timespec_ns(&times->latency.min);
+	double max = timespec_ns(&times->latency.max);
+
+	if (seconds > 0) {
+		printf("%9ld", seconds);
+	} else if (elapsed.tv_nsec >= 10 * 1000 * 1000) {
+		printf("%9.2f", fsec);
+	} else {
+		printf("%9.0f", fsec);
+	}
+
+	printf(" │ %'17.0f │ %'15.0f ∈ [%'6.0f .. %'7.0f]\n", iops, mean, min, max);
+	fflush(stdout);
+}
+
+/** Push an ioq request. */
+static bool push(struct ioq *ioq, enum ioq_nop_type type, struct times *lap) {
+	void *ptr = NULL;
+
+	// Track latency for a small fraction of requests
+	if (!lap->timing && (lap->pushed + 1) % 128 == 0) {
+		start_request(lap);
+		ptr = lap;
+	}
+
+	int ret = ioq_nop(ioq, type, ptr);
+	if (ret != 0) {
+		bfs_everify(errno == EAGAIN, "ioq_nop(%d)", (int)type);
+		return false;
+	}
+
+	++lap->pushed;
+	return true;
+}
+
+/** Pop an ioq request. */
+static bool pop(struct ioq *ioq, struct times *lap, bool block) {
+	struct ioq_ent *ent = ioq_pop(ioq, block);
+	if (!ent) {
+		return false;
+	}
+
+	if (ent->ptr) {
+		finish_request(lap);
+	}
+
+	ioq_free(ioq, ent);
+	++lap->popped;
+	return true;
+}
+
+/** ^C flag. */
+static atomic bool quit = false;
+
+/** ^C hook. */
+static void ctrlc(int sig, siginfo_t *info, void *arg) {
+	store(&quit, true, relaxed);
+}
+
+int main(int argc, char *argv[]) {
+	// Use CLOCK_MONOTONIC if available
+#if defined(_POSIX_MONOTONIC_CLOCK) && _POSIX_MONOTONIC_CLOCK >= 0
+	if (sysoption(MONOTONIC_CLOCK) > 0) {
+		clockid = CLOCK_MONOTONIC;
+	}
+#endif
+
+	// Enable thousands separators
+	setlocale(LC_ALL, "");
+
+	// -d: queue depth
+	long depth = 4096;
+	// -j: threads
+	long threads = 0;
+	// -t: timeout
+	double timeout = 5.0;
+	// -L|-H: ioq_nop() type
+	enum ioq_nop_type type = IOQ_NOP_LIGHT;
+
+	const char *cmd = argc > 0 ? argv[0] : "ioq";
+	int c;
+	while (c = getopt(argc, argv, ":d:j:t:LH"), c != -1) {
+		switch (c) {
+		case 'd':
+			if (xstrtol(optarg, NULL, 10, &depth) != 0) {
+				fprintf(stderr, "%s: Bad depth '%s': %s\n", cmd, optarg, errstr());
+				return EXIT_FAILURE;
+			}
+			break;
+		case 'j':
+			if (xstrtol(optarg, NULL, 10, &threads) != 0) {
+				fprintf(stderr, "%s: Bad thread count '%s': %s\n", cmd, optarg, errstr());
+				return EXIT_FAILURE;
+			}
+			break;
+		case 't':
+			if (xstrtod(optarg, NULL, &timeout) != 0) {
+				fprintf(stderr, "%s: Bad timeout '%s': %s\n", cmd, optarg, errstr());
+				return EXIT_FAILURE;
+			}
+			break;
+		case 'L':
+		 	type = IOQ_NOP_LIGHT;
+			break;
+		case 'H':
+		 	type = IOQ_NOP_HEAVY;
+			break;
+		case ':':
+			fprintf(stderr, "%s: Missing argument to -%c\n", cmd, optopt);
+			return EXIT_FAILURE;
+		case '?':
+			fprintf(stderr, "%s: Unrecognized option -%c\n", cmd, optopt);
+			return EXIT_FAILURE;
+		}
+	}
+
+	if (threads <= 0) {
+		threads = xsysconf(_SC_NPROCESSORS_ONLN);
+		if (threads > 8) {
+			threads = 8;
+		}
+	}
+	if (threads < 2) {
+		threads = 2;
+	}
+	--threads;
+
+	// Listen for ^C to print the summary
+	struct sighook *hook = sighook(SIGINT, ctrlc, NULL, SH_CONTINUE | SH_ONESHOT);
+
+	printf("I/O queue benchmark (%s)\n\n", bfs_version);
+
+	printf("[-d] depth:   %ld\n", depth);
+	printf("[-j] threads: %ld (including main)\n", threads + 1);
+	if (type == IOQ_NOP_HEAVY) {
+		printf("[-H] type:    heavy (with syscalls)\n");
+	} else {
+		printf("[-L] type:    light (no syscalls)\n");
+	}
+	printf("\n");
+
+	printf(" Time (s) │ Throughput (IO/s) │ Latency (ns/IO)\n");
+	printf("══════════╪═══════════════════╪═════════════════\n");
+	fflush(stdout);
+
+	struct ioq *ioq = ioq_create(depth, threads);
+	bfs_everify(ioq, "ioq_create(%ld, %ld)", depth, threads);
+
+	// Pre-allocate all the requests
+	while (ioq_capacity(ioq) > 0) {
+		int ret = ioq_nop(ioq, type, NULL);
+		bfs_everify(ret == 0, "ioq_nop(%d)", (int)type);
+	}
+	while (true) {
+		struct ioq_ent *ent = ioq_pop(ioq, true);
+		if (!ent) {
+			break;
+		}
+		ioq_free(ioq, ent);
+	}
+
+	struct times total, lap;
+	times_init(&total);
+	lap = total;
+
+	long seconds = 0;
+	while (!load(&quit, relaxed)) {
+		bool was_timing = lap.timing;
+
+		for (int i = 0; i < 16; ++i) {
+			bool block = ioq_capacity(ioq) == 0;
+			if (!pop(ioq, &lap, block)) {
+				break;
+			}
+		}
+
+		if (was_timing && !lap.timing) {
+			struct timespec elapsed;
+			gettime(&elapsed);
+			timespec_sub(&elapsed, &total.start);
+
+			if (elapsed.tv_sec > seconds) {
+				seconds = elapsed.tv_sec;
+				times_print(&lap, seconds);
+				times_lap(&total, &lap);
+			}
+
+			double ns = timespec_ns(&elapsed);
+			if (timeout > 0 && ns >= timeout * 1.0e9) {
+				break;
+			}
+		}
+
+		for (int i = 0; i < 8; ++i) {
+			if (!push(ioq, type, &lap)) {
+				break;
+			}
+		}
+	}
+
+	while (pop(ioq, &lap, true));
+	times_lap(&total, &lap);
+
+	if (load(&quit, relaxed)) {
+		printf("\r────^C────┼───────────────────┼─────────────────\n");
+	} else {
+		printf("──────────┼───────────────────┼─────────────────\n");
+	}
+	times_print(&total, 0);
+
+	ioq_destroy(ioq);
+	sigunhook(hook);
+	return 0;
+}