I encountered a problem when adding libssh2 support to qemu: http://lists.gnu.org/archive/html/qemu-devel/2013-03/msg04626.html
which was that my code always called libssh2_sftp_seek64 between every request. Because the requests come randomly, this makes sense from the point of view of making the code simple. There seems to be an impact on performance in my measurements of perhaps 1/5th - 1/3rd, and that appears to come down to libssh2 flushing readahead buffers when you call libssh2_sftp_seek64. I since changed the code of qemu to avoid calling libssh2_sftp_seek64 unless it is necessary, but the patch I'm attaching here should at least partially fix the problem at the libssh2 API level. To be honest I'm having a hard time measuring the impact of this change because the variability in my measurements is about the same as the benefit I'm expecting to see. Nevertheless the change should be obviously correct by inspection, so I don't see what harm it would do. Rich. _______________________________________________ libssh2-devel http://cool.haxx.se/cgi-bin/mailman/listinfo/libssh2-devel
