add -I interval option

-I INTERVAL option inserts sleep for interval (seconds) between
SSH connection attempts (issue #7).

include/mscp.h

@@ -43,7 +43,8 @@ struct mscp_opts {
 	size_t	max_chunk_sz;	/** maximum chunk size (default file size/nr_threads) */
 	size_t	buf_sz;		/** buffer size, default 16k. */
 	char	coremask[MSCP_MAX_COREMASK_STR]; /** hex to specifiy usable cpu cores */
-	int	max_startups;	/* sshd MaxStartups concurrent connections */
+	int	max_startups;	/** sshd MaxStartups concurrent connections */
+	int     interval;	/** interval between SSH connection attempts */
 
 	int	severity; 	/** messaging severity. set MSCP_SERVERITY_* */
 	int	msg_fd;		/** fd to output message. default STDOUT (0),

src/main.c

@@ -18,7 +18,8 @@
 void usage(bool print_help) {
 	printf("mscp " MSCP_BUILD_VERSION ": copy files over multiple ssh connections\n"
 	       "\n"
-	       "Usage: mscp [vqDHdNh] [-n nr_conns] [-m coremask] [-u max_startups]\n"
+	       "Usage: mscp [vqDHdNh] [-n nr_conns] [-m coremask]\n"
+	       "            [-u max_startups] [-I interval]\n"
 	       "            [-s min_chunk_sz] [-S max_chunk_sz] [-a nr_ahead] [-b buf_sz]\n"
 	       "            [-l login_name] [-p port] [-F ssh_config] [-i identity_file]\n"
 	       "            [-c cipher_spec] [-M hmac_spec] [-C compress] [-g congestion]\n"
@@ -31,11 +32,12 @@ void usage(bool print_help) {
 	printf("    -n NR_CONNECTIONS  number of connections "
 	       "(default: floor(log(cores)*2)+1)\n"
 	       "    -m COREMASK        hex value to specify cores where threads pinned\n"
-	       "    -u MAX_STARTUPS    number of concurrent outgoing connections "
+	       "    -u MAX_STARTUPS    number of concurrent SSH connection attempts "
 	       "(default: 8)\n"
+	       "    -I INTERVAL        interval between SSH connection attempts (default: 0)\n"
+	       "\n"
 	       "    -s MIN_CHUNK_SIZE  min chunk size (default: 64MB)\n"
 	       "    -S MAX_CHUNK_SIZE  max chunk size (default: filesize/nr_conn)\n"
-	       "\n"
 	       "    -a NR_AHEAD        number of inflight SFTP commands (default: 32)\n"
 	       "    -b BUF_SZ          buffer size for i/o and transfer\n"
 	       "\n"
@@ -253,7 +255,7 @@ int main(int argc, char **argv)
 	o.severity = MSCP_SEVERITY_WARN;
 
 	while ((ch = getopt(argc, argv,
-			    "n:m:u:s:S:a:b:vqDrl:p:i:F:c:M:C:g:HdNh")) != -1) {
+			    "n:m:u:I:s:S:a:b:vqDrl:p:i:F:c:M:C:g:HdNh")) != -1) {
 		switch (ch) {
 		case 'n':
 			o.nr_threads = atoi(optarg);
@@ -269,6 +271,9 @@ int main(int argc, char **argv)
 		case 'u':
 			o.max_startups = atoi(optarg);
 			break;
+		case 'I':
+			o.interval = atoi(optarg);
+			break;
 		case 's':
 			o.min_chunk_sz = atoi(optarg);
 			break;

src/mscp.c

@@ -80,8 +80,6 @@ struct src {
 #define non_null_string(s) (s[0] != '\0')
 
 
-
-
 static int expand_coremask(const char *coremask, int **cores, int *nr_cores)
 {
         int n, *core_list, core_list_len = 0, nr_usable, nr_all;
@@ -203,6 +201,11 @@ static int validate_and_set_defaut_params(struct mscp_opts *o)
 		return -1;
 	}
 
+	if (o->interval > 0) {
+		/* when the interval is set, establish SSH connections sequentially. */
+		o->max_startups = 1;
+	}
+
 	if (o->msg_fd == 0)
 		o->msg_fd = STDOUT_FILENO;
 
@@ -594,7 +597,22 @@ int mscp_join(struct mscp *m)
 	return ret;
 }
 
-/* copy thread related functions */
+/* copy thread-related functions */
+
+static void wait_for_interval(int interval)
+{
+	_Atomic static long next;
+	struct timeval t;
+	long now;
+
+	gettimeofday(&t, NULL);
+	now = t.tv_sec * 1000000 + t.tv_usec;
+
+	if (next - now > 0)
+		usleep(next - now);
+
+	next = now + interval * 1000000;
+}
 
 static void mscp_copy_thread_cleanup(void *arg)
 {
@@ -604,16 +622,17 @@ static void mscp_copy_thread_cleanup(void *arg)
 
 void *mscp_copy_thread(void *arg)
 {
-        sftp_session src_sftp, dst_sftp;
-        struct mscp_thread *t = arg;
+	sftp_session src_sftp, dst_sftp;
+	struct mscp_thread *t = arg;
 	struct mscp *m = t->m;
-        struct chunk *c;
+	struct chunk *c;
+	bool nomore;
+
+        pthread_cleanup_push(mscp_copy_thread_cleanup, t);
 
         if (t->cpu > -1) {
-                if (set_thread_affinity(pthread_self(), t->cpu) < 0) {
-			t->ret = -1;
-                        return NULL;
-		}
+                if (set_thread_affinity(pthread_self(), t->cpu) < 0)
+			goto err_out;
         }
 
 	if (sem_wait(m->sem) < 0) {
@@ -622,9 +641,12 @@ void *mscp_copy_thread(void *arg)
 		goto err_out;
 	}
 
-	mpr_notice(m->msg_fp, "connecting to %s for copy thread:%d...\n",
-		   m->remote, t->id);
-	t->sftp = ssh_init_sftp_session(m->remote, m->ssh_opts);
+	if (!(nomore = chunk_pool_is_empty(&m->cp))) {
+		if (m->opts->interval > 0)
+			wait_for_interval(m->opts->interval);
+		mpr_notice(m->msg_fp, "thread:%d connecting to %s\n", t->id, m->remote);
+		t->sftp = ssh_init_sftp_session(m->remote, m->ssh_opts);
+	}
 
 	if (sem_post(m->sem) < 0) {
 		mscp_set_error("sem_post: %s", strerrno());
@@ -632,8 +654,13 @@ void *mscp_copy_thread(void *arg)
 		goto err_out;
 	}
 
+	if (nomore) {
+		mpr_notice(m->msg_fp, "thread:%d no more connections needed\n", t->id);
+		goto out;
+	}
+
 	if (!t->sftp) {
-		mpr_err(m->msg_fp, "copy thread:%d: %s\n", t->id, mscp_get_error());
+		mpr_err(m->msg_fp, "thread:%d: %s\n", t->id, mscp_get_error());
 		goto err_out;
 	}
 
@@ -650,10 +677,6 @@ void *mscp_copy_thread(void *arg)
                 return NULL; /* not reached */
         }
 
-        pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
-        pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
-        pthread_cleanup_push(mscp_copy_thread_cleanup, t);
-
         while (1) {
                 c = chunk_pool_pop(&m->cp);
 		if (c == CHUNK_POP_WAIT) {
@@ -673,8 +696,8 @@ void *mscp_copy_thread(void *arg)
         pthread_cleanup_pop(1);
 
         if (t->ret < 0)
-		mpr_err(m->msg_fp, "copy failed: chunk %s 0x%010lx-0x%010lx\n",
-			c->p->path, c->off, c->off + c->len);
+		mpr_err(m->msg_fp, "thread:%d copy failed: %s 0x%010lx-0x%010lx\n",
+			t->id, c->p->path, c->off, c->off + c->len);
 
         return NULL;
 
@@ -682,10 +705,14 @@ err_out:
 	t->finished = true;
 	t->ret = -1;
 	return NULL;
+out:
+	t->finished = true;
+	t->ret = 0;
+	return NULL;
 }
 
 
-/* cleanup related functions */
+/* cleanup-related functions */
 
 static void free_src(struct list_head *list)
 {
@@ -751,19 +778,20 @@ void mscp_free(struct mscp *m)
 
 void mscp_get_stats(struct mscp *m, struct mscp_stats *s)
 {
+	int nr_finished = 0, nr_threads = 0;
 	struct mscp_thread *t;
-	bool finished = true;
 
 	s->total = m->total_bytes;
 	s->done = 0;
 
 	RWLOCK_READ_ACQUIRE(&m->thread_rwlock);
 	list_for_each_entry(t, &m->thread_list, list) {
+		nr_threads++;
 		s->done += t->done;
-		if (!t->finished)
-			finished = false;
+		if (t->finished)
+			nr_finished++;
 	}
 	RWLOCK_RELEASE();
 
-	s->finished = finished;
+	s->finished = nr_threads > 0 ? (nr_finished == nr_threads) : false;
 }

src/path.c

@@ -49,6 +49,10 @@ size_t chunk_pool_size(struct chunk_pool *cp)
 	return cp->count;
 }
 
+bool chunk_pool_is_empty(struct chunk_pool *cp)
+{
+	return list_empty(&cp->list);
+}
 
 struct chunk *chunk_pool_pop(struct chunk_pool *cp)
 {
@@ -68,7 +72,7 @@ struct chunk *chunk_pool_pop(struct chunk_pool *cp)
 	}
 	LOCK_RELEASE();
 
-	/* return CHUNK_POP_WAIT would be very rare case, because it
+	/* return CHUNK_POP_WAIT would be a rare case, because it
 	 * means copying over SSH is faster than traversing
 	 * local/remote file paths.
 	 */

src/path.h

@@ -62,6 +62,9 @@ bool chunk_pool_is_filled(struct chunk_pool *cp);
 /* return number of chunks in the pool */
 size_t chunk_pool_size(struct chunk_pool *cp);
 
+/* return true if chunk pool is empty (all chunks are already poped) */
+bool chunk_pool_is_empty(struct chunk_pool *cp);
+
 /* free chunks in the chunk_pool */
 void chunk_pool_release(struct chunk_pool *cp);
 

src/pymscp.c

@@ -97,6 +97,7 @@ static PyObject *wrap_mscp_init(PyObject *self, PyObject *args, PyObject *kw)
 		"coremask",	/* const char * */
 
 		"max_startups",	/* int */
+		"interval",	/* int */
 		"severity",	/* int, MSCP_SERVERITY_* */
 		"msg_fd",	/* int */
 
@@ -118,7 +119,7 @@ static PyObject *wrap_mscp_init(PyObject *self, PyObject *args, PyObject *kw)
 		"enable_nagle",		/* bool */
 		NULL,
 	};
-	const char *fmt = "si" "|" "ii" "kkk" "s" "iii" "ssss" "ssssss" "ipp";
+	const char *fmt = "si" "|" "ii" "kkk" "s" "iiii" "ssss" "ssssss" "ipp";
 	char *coremask = NULL;
 	char *login_name = NULL, *port = NULL, *config = NULL, *identity = NULL;
 	char *cipher = NULL, *hmac = NULL, *compress = NULL, *ccalgo = NULL;
@@ -146,6 +147,7 @@ static PyObject *wrap_mscp_init(PyObject *self, PyObject *args, PyObject *kw)
 					  &i->mo.buf_sz,
 					  &coremask,
 					  &i->mo.max_startups,
+					  &i->mo.interval,
 					  &i->mo.severity,
 					  &i->mo.msg_fd,
 					  &login_name,

test/test_e2e.py

@@ -300,6 +300,20 @@ def test_dont_truncate_dst(mscp, src_prefix, dst_prefix):
     assert md5_before == md5_after
     f.cleanup()
 
+@pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
+def test_set_conn_interval(mscp, src_prefix, dst_prefix):
+    srcs = []
+    dsts = []
+    for x in range(500):
+        srcs.append(File("src/file{}".format(x), size = 128).make())
+        dsts.append(File("dst/file{}".format(x)))
+    run2ok([mscp, "-H", "-vvv", "-I", 1, src_prefix + "src", dst_prefix + "dst"])
+
+    for src, dst in zip(srcs, dsts):
+        assert check_same_md5sum(src, dst)
+        src.cleanup()
+        dst.cleanup()
+
 compressions = ["yes", "no", "none"]
 @pytest.mark.parametrize("src_prefix, dst_prefix", param_remote_prefix)
 @pytest.mark.parametrize("compress", compressions)