Hi, Wondering about the speed differential between scp and sftp with libssh2, I built a profile version (--disable-shared CFLAGS="-pg") to see if anything obvious jumped out at me...
The main thing that does jump out (comparing scp_nonblock and sftp_nonblock in examples/simple) is that sftp makes many more calls to libssh2_packet_read than scp - about 10 times as many. This can be reduced by using a larger buffer, I tried 4Kb, 16Kb and 32Kb and saw improvements for each, but still, for a large file from localhost, an scp copy is 4 times faster than an sftp copy (it makes 4 times as many calls to libssh2_packet_read), enlarging the buffer again (128Kb now) makes sftp faster than scp. This proves, yet again, that larger reads are better, and shows that libssh2 is not, in fact, slow at sftp transfers. Yay! Thank you, Peter Unchanged scp_nonblock real 0m19.600s user 0m5.622s sys 0m5.709s 1Kb buffer (i.e. unchanged) sftp_nonblock (no times, because I control-Ced after 10 minutes) 32Kb buffer - sftp_nonblock real 1m22.487s user 0m21.022s sys 0m54.886s 128Kb buffer - sftp_nonblock real 0m7.775s user 0m2.431s sys 0m3.637s ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ libssh2-devel mailing list libssh2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libssh2-devel
