Bug 985113 - SFTP transfers handled by kio_sftp are much slower than those handled by scp
SFTP transfers handled by kio_sftp are much slower than those handled by scp
Product: Fedora
Classification: Fedora
Component: kde-runtime (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Ngo Than
Fedora Extras Quality Assurance
Depends On:
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Reported: 2013-07-16 16:02 EDT by Alex G.
Modified: 2015-06-29 08:05 EDT (History)
8 users (show)

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Doc Type: Bug Fix
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Last Closed: 2015-06-29 08:05:16 EDT
Type: Bug
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Description Alex G. 2013-07-16 16:02:38 EDT
Description of problem:
On a gigabit network, I can transfer files with an average throughput of 80 Mib/s with scp. Transferring the exact files using Dolphin and kio_sftp gives an average throughput of only 12 MiB/s.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
0.a. Setup a gigabit network with at least two machines
0.b. Set up ssh access on machine 2
1. On machine1 open Dolphin
2. Click on the "address" bar. The bar becomes editable
3. enter "sftp://<user>@<ip_of_machine2>:/home/<user>"
4. Enter password when prompted for one
5. After directory loads, "copy"(Ctrl-C) a large local, and "paste" (Ctrl-V) it in the Dolphin window. This starts the transfer.
6. Use the "Network Management" widget to observe transfer speed
7. Try to copy the same or a similar file with scp:
 $ scp large.file <user>@<ip_of_machine2>:/home/<user>/
8 Observe the transfer speed either by watching scp output, or using the "Network Management" widget.

Actual results:
kio_sftp: about 12 MiB/s average throughput, and 80% cpu (core) usage
scp: about 80 MiB/s average throughput, and 35% cpu (core) usage

Expected results:
Same throughput using both scp and kio_sftp, and same cpu usage.

Additional info:
I transferred one contiguous 8 GiB file. The network was comprised of standard CAT 5E cabling with a low-cost gigabit switch.
Comment 1 Alex G. 2014-01-21 15:59:02 EST
Ping? Issue is still here with latest F20 packages.
Comment 2 Rex Dieter 2014-01-24 10:46:25 EST
We're not likely to work on this downstream in fedora (largely due to time and expertise constraints).

If you have continued interest in resolving this, contacting upstream (via bugs.kde.org or mailing lists) will have a better chance at yielding results.
Comment 3 Fedora End Of Life 2015-05-29 05:11:10 EDT
This message is a reminder that Fedora 20 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 20. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
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Comment 4 Fedora End Of Life 2015-06-29 08:05:16 EDT
Fedora 20 changed to end-of-life (EOL) status on 2015-06-23. Fedora 20 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

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