FTP Plugin: High CPU load during download from local server

[crystalidea]

While I copy a file (300 MB) from a local FTP server, the process salamand.exe eats 99% of cpu time.

[cincura.net]

While I copy a file (300 MB) from a local FTP server, the process salamand.exe eats 99% of cpu time.

And if you use another FTP client, there's no huge load?

PS: If the transfer is very fast, the computer must be loaded.

[Petr Solin]

Yes, FTP is optimized for lower speeds (e.g. up to 1 MB/s) than local transfers (e.g. 30 MB/s), so processor load is high during such transfers.

What is transfer speed for this your transfer?

[crystalidea]

Transfer rate is about 5 MB/s, well what's the solution?

[Jan Rysavy]

Transfer rate is about 5 MB/s, well what's the solution?

Could you please test another FTP clients (FileZilla, TC)?
1) Measure the transfer speed (if it is limited by CPU load in the SS case)
2) Measure the CPU load
3) Could you test the upload too? (including SS)

Thank you.

Which FTP server are you using?

[crystalidea]

TC:
Download: 9 MB/s, CPU Load: 10-15%
Upload: 5.5 MB/s, CPU Load: 25-30%

SS:

Download: 5 MB/s, Cpu Load: 60-70%
Upload: 4-4.5 MB/s, CPU Load: 30%

FTP Server: Titan FTP Server 4

[Jan Rysavy]

Which FTP server are you using?

Could you describe the structure of copied files? (a lot of small files/directories or one big file?)

[Jan Rysavy]

While I copy a file (300 MB) from a local FTP server, the process salamand.exe eats 99% of cpu time.

TC:
Download: 9 MB/s, CPU Load: 10-15%
Upload: 5.5 MB/s, CPU Load: 25-30%

SS:

Download: 5 MB/s, Cpu Load: 60-70%
Upload: 4-4.5 MB/s, CPU Load: 30%

You wrote that SS eats 99% of CPU. Then 60-70%. I don't understand...

[Jan Rysavy]

Moderator: More detailed subject.

[crystalidea]

FTP Server: Titan FTP Server 4
One big file (a couple of hundreds megabytes).
look at the perfomance graph (procexp):
www.xpis.alfaspace.net/untitled.png_
(it grew hi when I started copying)

[Jan Rysavy]

Are you using Servant Salamander 2.5 beta 11?
(Petr Solin did several optimizations in FTP plugin)

[crystalidea]

Of cause. like new logos

[Jan Rysavy]

Could you please measure the total transfer time in SS and TC?

I can reproduce the higher CPU load of SS compares to TC (we know that, as Petr Solin wrote above, it is by plugin design) but the total transfer time is nearly SAME in both FTP clients (in my test case).

local FTP server

Do you run the FTP server on the same machine as FTP client? Or do you mean the local network?

[crystalidea]

Local server means within our office local network. The server runs Windows 2003 Server.

[Jan Rysavy]

We don't see the problem here. Please look at following CPU load charts from our office.



There are many factors in the game: used operating systems on both server and client sides, network settings, actual network load, disks fragmentation, used FTP server, etc. Results will differ from case to case.