#5686 closed Patch (rejected)
improved SFTP upload performance patch
| Reported by: | BJB | Owned by: | |
|---|---|---|---|
| Priority: | normal | Component: | FileZilla Client |
| Keywords: | Cc: | ||
| Component version: | Operating system type: | Windows | |
| Operating system version: |
Description
Hi,
I realized a long time ago that uploads for SFTP were slower than they should be for connections that could benefit from large window scaling. The problem was in the PuTTY underlying code.
I finally dug out the source code to figure out why. Here is a patch that enables that behavior on Windows. I am using the patched version on my machine for a month now and I've not noticed any problems.
Regards
Attachments (1)
Change History (2)
by , 14 years ago
| Attachment: | fz-windows-upload-speed.diff added |
|---|
comment:1 by , 14 years ago
| Resolution: | → rejected |
|---|---|
| Status: | new → closed |
The change to the constants in ssh.c is basically a NOP as it is only used as fallback on servers that do not support large SSH windows.
There is no such thing as a "TCP send window scaling". A 4 MiB send buffer is detrimental to memory consumption and not really useful.
The default size of the send buffer on Windows which is a mere 8 KiB. So in each iteration through its sending loop, PuTTY can only send 8 KiB of data which induces additional delays which are the actual cause of the slowdown.
The true reason why it appears to work is that the default buffer size is a mere 8K under Windows.
A change to use slightly larger send buffer resulting in considerably improved transfer speeds has been committed to the SVN repository a while ago.
For future submissions, please carefully analyze the root cause of the problem and base your patch against the latest trunk head from the repository.
patch