TCP/IP buffer size

duo_core · 01-12-2007, 02:33 PM

Hello all,

I noticed that the maximum of TCP/IP buffer size is 256KB.
But this value is too small. Can it be larger? 512KB, 1024KB, 2048KB, ... 8196KB, etc.

This is bottleneck. I try to download a same file with v2 and v3.
with v2 I can reach 10MB/s, but
with v3 I can only reach roughly 5MB/s.

PS: Can you make another option: to make the Local Path Selector not editable? In v2, when you click on the Local Pach Selector, you will see the dropdown list. But in v3, this edit box become focused and you can change the path in it.

best regards
dc

MxxCon · 01-13-2007, 02:40 PM

you transfer faster not nessarly becuase if a larger buffer size. for many people smaller size will provide better speed.

comparing v2 with v3

. v3 have been out for like what, 3 years now?
if you wanted that changed, you should've complained when v3 was in beta.
you should click on drive icon and not on text to get dropdown list

duo_core · 01-13-2007, 04:15 PM

What is the disadvantage, if you provide more buffer size options? And I think there's a real issue behind it. Previously I tried to download an ISO from a fast FTP with v3 on single core machine. It is even worth. The max. speed is 5MB/s, and the CPU usage is 100%. Now I am using duo core machine. The CPU usage is reduced to roughly 50%, but the max. speed is still 5MB/s. But with v2 ~> no problem at all. CPU usage is 20-50%, max. speed 10-12MB/s
To the second answer: I know I can do this. But here, I am just asking if this could be an option for those users (like me).
Code:
```
if bNonEditablePathSelector then
  LeftPathComboBox.Style:=csDropDownList; //that's all
```

MxxCon · 01-13-2007, 10:10 PM

something wrong with your setup.
i can transfer at near 100mbit with <10% cpu usage.

and once again, larger buffer size isn't better...

duo_core · 01-13-2007, 10:50 PM

I can reprocedure this issue everytime (on my two machines)

downloaded the latest BETA,
install in a new folder.
run the program.
add a FTP site and start download

everything is default value. Have I forget to tune something?

BTW: I just test v2 and v3 on my both machines.
v2 can reach always 100mbit/s
v3 can reach only 50mbit/s

My machine #1: Intel Core Duo E6400, 2GB DDR667 (dual channel), 320GB SATA 2.0 7200rpm, WinXP Pro+SP2
My machine #2: IBM T43, Centrino 1,73, 1GB DDR533 (dual channel), 80GB 5400rpm, WinXP Pro+SP2

bigstar · 01-16-2007, 07:34 PM

1. For most sites over the internet you'll see a very small packet size, probably 1460 bytes. The size of an ethernet packet. Some servers will use 8K (i.e. GLFTPD) but the majority don't. You're probably wondering why we anything close to 256k, well normally you don't. However when the site is really far away and there is high lantency between you and the site having a higher buffer allows more data to be read per cycle.

As far as using something larger than 256k. That would be pretty much overkill and I haven't seen any reason to support such said size.

As MxxCon pointed out v2 is quite old, I don't have the source code at hand for that version, So I don't know what buffer size was used. I'm thinking it was either 8k or 32k.

The routine for transferring files is single threaded. As such FlashFXP should perform just as well on a single cpu vs duel core cpu.

On my lan using Gene6 FTPd, I have no problem getting 40MB/s file transfers. The limiting factor being the hard drives.

CPU usage should be quite low unless you're doing a LAN, SSL, or MODE Z transfer.

2. To have this as an option is unnecessary.

duo_core · 01-17-2007, 07:00 PM

Thanks. Finally I have found out the problem ~> "MODE Z"

By default this option is turned on. When I switch this option off, I can reach 10MB/s again. (I mean, I try to download files from another FTP site on LAN not from localhost.)

To note that "Bypass for local (LAN) sites FTP sites" is already turned on. I think this function is broken (defect), isn't it?

I have a suggestion about File Exist Rules: We can choose different actions when the file size is larger, smaller or same. mum.. Usually if a file is small than 100kb, I always let program overwrite it. So, do you think, it might be helpful to add such an option in File Exists Rules "when File size is more/less than xxx KB"

thanks