From 9e56b84c41efcaf3349f82a93c3dc854e172e5c4 Mon Sep 17 00:00:00 2001 From: Kamil Dudka Date: Fri, 9 Aug 2013 16:22:08 +0200 Subject: [PATCH 4/5] partially revert "window_size: explicit adjustments only" This partially reverts commit 03ca9020756a4e16f0294e5b35e9826ee6af2364 in order to fix extreme slowdown when uploading to localhost via SFTP. I was able to repeat the issue on RHEL-7 on localhost only. It did not occur when uploading via network and it did not occur on a RHEL-6 box with the same version of libssh2. The problem was that sftp_read() used a read-ahead logic to figure out the window_size, but sftp_packet_read() called indirectly from sftp_write() did not use any read-ahead logic. --- src/channel.c | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/src/channel.c b/src/channel.c index 4f41e1f..d4ffdce 100644 --- a/src/channel.c +++ b/src/channel.c @@ -1759,6 +1759,15 @@ ssize_t _libssh2_channel_read(LIBSSH2_CHANNEL *channel, int stream_id, channel->read_state = libssh2_NB_state_created; } + /* + * =============================== NOTE =============================== + * I know this is very ugly and not a really good use of "goto", but + * this case statement would be even uglier to do it any other way + */ + if (channel->read_state == libssh2_NB_state_jump1) { + goto channel_read_window_adjust; + } + rc = 1; /* set to >0 to let the while loop start */ /* Process all pending incoming packets in all states in order to "even @@ -1867,6 +1876,26 @@ ssize_t _libssh2_channel_read(LIBSSH2_CHANNEL *channel, int stream_id, more off the network again */ channel->read_state = libssh2_NB_state_created; + if(channel->remote.window_size < (LIBSSH2_CHANNEL_WINDOW_DEFAULT*30)) { + /* the window is getting too narrow, expand it! */ + + channel_read_window_adjust: + channel->read_state = libssh2_NB_state_jump1; + /* the actual window adjusting may not finish so we need to deal with + this special state here */ + rc = _libssh2_channel_receive_window_adjust(channel, + (LIBSSH2_CHANNEL_WINDOW_DEFAULT*60), 0, NULL); + if (rc) + return rc; + + _libssh2_debug(session, LIBSSH2_TRACE_CONN, + "channel_read() filled %d adjusted %d", + bytes_read, buflen); + /* continue in 'created' state to drain the already read packages + first before starting to empty the socket further */ + channel->read_state = libssh2_NB_state_created; + } + return bytes_read; } -- 1.7.1