Larger TCP/IP buffer size options

I've recently upgraded to a 150/10 mbps cable service, and I'm finding FlashFXP can't keep up with the new speeds. It has always been very sensitive to latency and I suspect even larger TCP/IP buffers could mitigate that weakness. I'm in the unfortunate position of managing a handful of servers scattered around the globe, and when I have to move large files things go very slowly with FlashFXP compared to other clients. It doesn't happen all that often for me, as I am typically editing text files 99% of the time, but when it does happen I find myself switching to FileZilla for the larger transfers (400mb and up)

What I would love to see is buffer sizes up to 4096kb. It's an educated guess but I believe this would saturate my connection both ways, as right now with a 1024kb receive buffer I'm only getting 50 mbps. I find I only need 512kb to saturate my 10 mbps upload so that's no problem, at least on my residential line.

And this is presuming that with default buffers or lower you haven't gained any benefit over larger buffers?

Larger buffers not always equal better performance or faster speeds.

Also other clients probably not using such high buffers settings or are they?

Also because I think you havent mentioned it, what version ffxp are you on and if not latest 4.4.1 build 2000 can you upgrade to latest and see.

A larger TCP/IP buffer isn't going to solve the problem.

For non-LAN transfers typically the best solution (assuming you're using Windows 7 and up) is to use the (default) value, this allows the Windows OS to automatically handle the TCP/IP buffer size and scale it as needed to help offset any slow down caused by high latency.

What is your Windows version and FlashFXP version/build?

You indicate that FileZilla gives you better speeds but it is my understanding that it uses 16KB send and 4KB receive.

Have you tested FlashFXP using smaller TCP/IP buffers if the OS (default) isn't giving you good results?

I am on 4.4.1 build 1998, which is the latest version shown on your site, as well as within FlashFXP's self-update feature. Windows 7 x64 SP1, fully updated. Intel dual Xeon 12 core 2.8ghz, 48gb ram, SSD. Windows TCP auto-tuning enabled.

FileZilla's default buffer is 4096kb, and that has been the default for at least 3 years to my knowledge. I can easily reach 18 MB/s with it and other clients (or iperf).

Back to FlashFXP, I have done a number of tests with the receive buffer set to (default), (auto) and 1024kb. In all three cases, my file transfer never exceeded 6 MB/s. Conversely, for sending if I use (default) or (auto), the maximum speed is 350 KB/s. If I manually set the send buffer to 256kb or higher, I get the full 1200 KB/s upload speed.

The remote FTP host is a private, dedicated server that is otherwise idle, with a gigabit connection to the world (which it can saturate). The RTT is 106ms since it is in Europe and I'm in Canada. I've run these tests multiple times to ensure my results weren't unfairly affected by transatlantic congestion.

I'm a bit puzzled by your statement that larger buffers don't always result in better performance. That kind-of goes against everything I know as a developer... obviously there can be other bottlenecks along the path, but in this case I know from experience that the link can support much higher speeds with the right settings. That's my sole concern here. I can't remember the last time I used only a 1mb buffer for anything network-related.

-Bill

Originally Posted by X3

And this is presuming that with default buffers or lower you haven't gained any benefit over larger buffers?

Larger buffers not always equal better performance or faster speeds.

Also other clients probably not using such high buffers settings or are they?

Also because I think you havent mentioned it, what version ffxp are you on and if not latest 4.4.1 build 2000 can you upgrade to latest and see.

(This is an advanced configuration override, please use with care)

Open the FlashFXP.ini data file in a text editor such as notepad

under the [main] section find the key "RPS"

RPS=<value>

Set the value to 4096

RPS=4096

Save the file

This will increase the recv TCP/IP buffer size to 4096 KB

To change the send TCP/IP buffer size do the same thing but find the key "SPS"

Start FlashFXP and the settings in the Preferences dialog will be disabled with the word "custom" indicating the values have been successfully changed, Test your speeds and please let us know your results. (Make sure your site profile is configured to use the global settings, there is no per-site custom override setting.)

Also if you could please open a windows command prompt (cmd) and type "netsh int tcp show global" and let us know the values you're using for your OS. Thanks.