[PATCH] Improving sftp client performance

[mouring at etoh.eviladmin.org]

No it was not in the CVS tree yet.  There was still discussions as to the
implementation.  I have a version that does not do more more then two
overlapping writes.

I'll have to take a look at your patch a little closer, but I worry about
attempting to optimize the number of writes/reads done in a single
sitting.  This could feesable change per hardware, per network, etc.  If
we want to go this way I really suggest we flesh out that defination using
-r.  That way the user can optimize it for themselves.  With -r 1 mimicing
the current behavior.  Then set a default (2 - 4) if -r is not used.

Attached is my version of the upload patch.

--- ../../ssh/sftp-client.c	Wed Dec 19 18:00:49 2001
+++ ../sftp-client.c	Tue Dec 25 14:00:00 2001
@@ -813,7 +813,7 @@
     int pflag)
 {
 	int local_fd;
-	u_int handle_len, id;
+	u_int handle_len, id, ackid;
 	u_int64_t offset;
 	char *handle;
 	Buffer msg;
@@ -861,6 +861,7 @@
 		return(-1);
 	}

+	ackid = id + 1;
 	/* Read from local and write to remote */
 	offset = 0;
 	for (;;) {
@@ -878,26 +879,30 @@
 		if (len == -1)
 			fatal("Couldn't read from \"%s\": %s", local_path,
 			    strerror(errno));
-		if (len == 0)
+
+		if (len != 0) {
+			buffer_clear(&msg);
+			buffer_put_char(&msg, SSH2_FXP_WRITE);
+			buffer_put_int(&msg, ++id);
+			buffer_put_string(&msg, handle, handle_len);
+			buffer_put_int64(&msg, offset);
+			buffer_put_string(&msg, data, len);
+			send_msg(fd_out, &msg);
+			debug3("Sent message SSH2_FXP_WRITE I:%d O:%llu S:%u",
+		    	    id, (unsigned long long)offset, len);
+		} else if (ackid > id)
 			break;

-		buffer_clear(&msg);
-		buffer_put_char(&msg, SSH2_FXP_WRITE);
-		buffer_put_int(&msg, ++id);
-		buffer_put_string(&msg, handle, handle_len);
-		buffer_put_int64(&msg, offset);
-		buffer_put_string(&msg, data, len);
-		send_msg(fd_out, &msg);
-		debug3("Sent message SSH2_FXP_WRITE I:%d O:%llu S:%u",
-		    id, (unsigned long long)offset, len);
-
-		status = get_status(fd_in, id);
-		if (status != SSH2_FX_OK) {
-			error("Couldn't write to remote file \"%s\": %s",
-			    remote_path, fx2txt(status));
-			do_close(fd_in, fd_out, handle, handle_len);
-			close(local_fd);
-			goto done;
+		if (id > ackid || (len == 0 && id == ackid)) {
+			status = get_status(fd_in, ackid);
+			if (status != SSH2_FX_OK) {
+				error("Couldn't write to remote file \"%s\": %s",
+				    remote_path, fx2txt(status));
+				do_close(fd_in, fd_out, handle, handle_len);
+				close(local_fd);
+				goto done;
+			}
+			ackid++;
 		}
 		debug3("In write loop, got %d offset %llu", len,
 		    (unsigned long long)offset);