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partially revert "window_size: explicit adjustments only"

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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.
This commit is contained in:
Kamil Dudka 2013-08-12 17:43:52 +02:00 committed by Daniel Stenberg
parent e6c46cc249
commit 61e40a32ff
1 changed files with 30 additions and 0 deletions
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30
src/channel.c
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@ -1760,6 +1760,15 @@ ssize_t _libssh2_channel_read(LIBSSH2_CHANNEL *channel, int stream_id,
channel->read_state = libssh2_NB_state_created; 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 */ rc = 1; /* set to >0 to let the while loop start */
/* Process all pending incoming packets in all states in order to "even /* Process all pending incoming packets in all states in order to "even
@ -1868,6 +1877,27 @@ ssize_t _libssh2_channel_read(LIBSSH2_CHANNEL *channel, int stream_id,
more off the network again */ more off the network again */
channel->read_state = libssh2_NB_state_created; 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; return bytes_read;
} }