add -m coremask option

src/main.c

@@ -50,6 +50,7 @@ struct mscp_thread {
 	sftp_session    sftp;
 
 	pthread_t       tid;
+	int		cpu;
 	size_t          done;           /* copied bytes */
 	bool            finished;
 	int		ret;
@@ -85,7 +86,7 @@ int list_count(struct list_head *head)
 void usage(bool print_help) {
 	printf("mscp v" VERSION ": copy files over multiple ssh connections\n"
 	       "\n"
-	       "Usage: mscp [vqDCHdh] [-n nr_conns]\n"
+	       "Usage: mscp [vqDCHdh] [-n nr_conns] [-m coremask]\n"
 	       "            [-s min_chunk_sz] [-S max_chunk_sz]\n"
 	       "            [-b sftp_buf_sz] [-B io_buf_sz] [-a nr_ahead]\n"
 	       "            [-l login_name] [-p port] [-i identity_file]\n"
@@ -96,6 +97,7 @@ void usage(bool print_help) {
 		return;
 
 	printf("    -n NR_CONNECTIONS  number of connections (default: half of # of cpu cores)\n"
+	       "    -m COREMASK        hex value to specify cores where threads pinned\n"
 	       "    -s MIN_CHUNK_SIZE  min chunk size (default: 64MB)\n"
 	       "    -S MAX_CHUNK_SIZE  max chunk size (default: filesize / nr_conn)\n"
 	       "\n"
@@ -164,15 +166,70 @@ err_out:
 	return NULL;
 }
 
+int expand_coremask(const char *coremask, int **cores, int *nr_cores)
+{
+	int n, *core_list, core_list_len = 0, nr_usable, nr_all;
+	char c[2] = { 'x', '\0' };
+	const char *_coremask;
+	long v, needle;
+
+	/*
+	 * This function returns array of usabe cores in `cores` and
+	 * returns the number of usabel cores (array length) through
+	 * nr_cores.
+	 */
+
+	if (strncmp(coremask, "0x", 2) == 0)
+		_coremask = coremask + 2;
+	else
+		_coremask = coremask;
+
+	core_list = realloc(NULL, sizeof(int) * 64);
+	if (!core_list) {
+		pr_err("failed to realloc: %s\n", strerrno());
+		return -1;
+	}
+
+	nr_usable = 0;
+	nr_all = 0;
+	for (n = strlen(_coremask) - 1; n >=0; n--) {
+		c[0] = _coremask[n];
+		v = strtol(c, NULL, 16);
+		if (v == LONG_MIN || v == LONG_MAX) {
+			pr_err("invalid coremask: %s\n", coremask);
+			return -1;
+		}
+
+		for (needle = 0x01; needle < 0x10; needle <<= 1) {
+			nr_all++;
+ 			if (v & needle) {
+				nr_usable++;
+				core_list = realloc(core_list, sizeof(int) * nr_usable);
+				if (!core_list) {
+					pr_err("failed to realloc: %s\n", strerrno());
+					return -1;
+				}
+				core_list[nr_usable - 1] = nr_all - 1;
+			}
+		}
+	}
+
+	*cores = core_list;
+	*nr_cores = nr_usable;
+	return 0;
+}
+
 int main(int argc, char **argv)
 {
 	struct mscp m;
 	struct ssh_opts opts;
 	int min_chunk_sz = DEFAULT_MIN_CHUNK_SZ;
 	int max_chunk_sz = 0;
+	char *coremask = NULL;;
 	int verbose = 1;
 	bool dryrun = false;
 	int ret = 0, n;
+	int *cores, nr_cores;
 	char ch;
 
 	memset(&opts, 0, sizeof(opts));
@@ -187,7 +244,7 @@ int main(int argc, char **argv)
 	nr_threads = (int)(nr_cpus() / 2);
 	nr_threads = nr_threads == 0 ? 1 : nr_threads;
 
-	while ((ch = getopt(argc, argv, "n:s:S:b:B:a:vqDl:p:i:c:CHdh")) != -1) {
+	while ((ch = getopt(argc, argv, "n:m:s:S:b:B:a:vqDl:p:i:c:CHdh")) != -1) {
 		switch (ch) {
 		case 'n':
 			nr_threads = atoi(optarg);
@@ -196,6 +253,9 @@ int main(int argc, char **argv)
 				return 1;
 			}
 			break;
+		case 'm':
+			coremask = optarg;
+			break;
 		case 's':
 			min_chunk_sz = atoi(optarg);
 			if (min_chunk_sz < getpagesize()) {
@@ -288,20 +348,29 @@ int main(int argc, char **argv)
 
 	pprint_set_level(verbose);
 
+	if (argc - optind < 2) {
+		/* mscp needs at lease 2 (src and target) argument */
+		usage(false);
+		return 1;
+	}
+	m.target = argv[argc - 1];
+
 	if (max_chunk_sz > 0 && min_chunk_sz > max_chunk_sz) {
 		pr_err("smaller max chunk size than min chunk size: %d < %d\n",
 		       max_chunk_sz, min_chunk_sz);
 		return 1;
 	}
 
-	if (argc - optind < 2) {
-		/* mscp needs at lease 2 (src and target) argument */
-		usage(false);
-		return 1;
+	/* expand usable cores from coremask */
+	if (coremask) {
+		if (expand_coremask(coremask, &cores, &nr_cores) < 0)
+			return -1;
+		pprint(1, "cpu cores:");
+		for (n = 0; n < nr_cores; n++)
+			pprint(1, " %d", cores[n]);
+		pprint(1, "\n");
 	}
 
-	m.target = argv[argc - 1];
-
 	/* create control session */
 	m.host = find_hostname(optind, argc, argv);
 	if (!m.host) {
@@ -350,6 +419,11 @@ int main(int argc, char **argv)
 		struct mscp_thread *t = &threads[n];
 		t->mscp = &m;
 		t->finished = false;
+		if (!coremask)
+			t->cpu = -1;
+		else
+			t->cpu = cores[n % nr_cores];
+
 		pprint3("connecting to %s for a copy thread...\n", m.host);
 		t->sftp = ssh_make_sftp_session(m.host, m.opts);
 		if (!t->sftp) {
@@ -426,6 +500,11 @@ void *mscp_copy_thread(void *arg)
 	sftp_session sftp = t->sftp;
 	struct chunk *c;
 
+	if (t->cpu > -1) {
+		if (set_thread_affinity(pthread_self(), t->cpu) < 0)
+			return NULL;
+	}
+
 	pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
 	pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
 	pthread_cleanup_push(mscp_copy_thread_cleanup, t);

src/platform.c

@@ -24,6 +24,14 @@ int nr_cpus()
 
 	return n;
 }
+
+int set_thread_affinity(pthread_t tid, int core)
+{
+	errno = ENOTSUP;
+	pr_err("setting thread afinity is not implemented on apple\n");
+	return -1;
+}
+
 #endif
 
 #ifdef linux
@@ -34,5 +42,19 @@ int nr_cpus()
 		return CPU_COUNT(&cpu_set);
 	return -1;
 }
+
+int set_thread_affinity(pthread_t tid, int core)
+{
+	cpu_set_t target_cpu_set;
+	int ret = 0;
+
+	CPU_ZERO(&target_cpu_set);
+	CPU_SET(core, &target_cpu_set);
+	ret = pthread_setaffinity_np(tid, sizeof(target_cpu_set), &target_cpu_set);
+	if (ret < 0)
+		pr_err("failed to set thread/cpu affinity for core %d: %s",
+		       core, strerrno());
+	return ret;
+}
 #endif
 

src/platform.h

@@ -1,6 +1,9 @@
 #ifndef _PLATFORM_H_
 #define _PLATFORM_H_
 
+#include <pthread.h>
+
 int nr_cpus();
+int set_thread_affinity(pthread_t tid, int core);
 
 #endif /* _PLATFORM_H_ */

test/test_e2e.py

@@ -150,6 +150,18 @@ def test_min_chunk(mscp, src_prefix, dst_prefix):
     src.cleanup()
     dst.cleanup()
 
+@pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
+def test_thread_affinity(mscp, src_prefix, dst_prefix):
+    src = File("src", size = 64 * 1024).make()
+    dst = File("dst")
+
+    run2ok([mscp, "-H", "-n", 4, "-m", "0x01", "-s", 8192, "-S", 65536,
+            src_prefix + src.path, dst_prefix + dst.path])
+    assert check_same_md5sum(src, dst)
+
+    src.cleanup()
+    dst.cleanup()
+
 @pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
 def test_cannot_override_file_with_dir(mscp, src_prefix, dst_prefix):
     src = File("src", size = 128).make()