KDE Frameworks 5.53 Will Have An Important KIO Performance Fix

[ermo]

what is the effect of this improvement?

Much fast. So glory.

[cl333r]

It must be a new and non-standard (posix or whatever) syscall cause I've never heard about it before. Seems a very good idea, I've always thought how when copying your file you really do a lot of proxy copies in between because of how kernel/userspace work, and was wondering if something like sendfile was possible at all.

Anyway, I guess from now on I'd do like

IF __linux___
// use sendfile
ELSE
// do the standard copy operations

[Michael]

It must be a new and non-standard (posix or whatever) syscall cause I've never heard about it before.

sendfile has been around since the Linux 2.2~2.4 days.

[markg85]

sigh... Important... Well, not "that" important.
If you look at the code change it's merely to detect sendfile. That, in a nutshell, is used to make copies with "zero copy overhead"[1].
That perk is used in file copies. The patch is in KIO's file slave, which is for your local files [2]. So literally copy a file from X to Y.

I'm not quite sure (but still fairly) that you will hardly notice this for local files. It might be a few percent faster. The real big win imho in this case is equally fast (or slightly faster) file copies while reducing memory consumption.

[1] It's not 0. But it prevents copies from userspace -> kernel space -> userspace. It keeps it all nice and tight in the kernel thus reducing the copies, not 0.
[2] Or in other words, everything that is mounted outside using KIO is local, which is everything that is available through file://....

[M@GOid]

Hi,
I hope you're joking, if not, I'm sorry!
This was not a prank.
For me is indeed not working.
At least with my current setup:
Kubuntu 18.10
Default session type (not Wayland)
Workspace theme: Breeze Dark
Window decoration: WindowsK10-dark (Border size: Normal)
Monitor: 4K

Relax man, it was just 2 tabs open :-)

[markc]

With NFS 1Gbit eth0 to another laptop I can get up to 110 Mbytes/sec transfer speed when I use rsync over NFS between the 2 machines. Last night I thought I'd try Dolphin and drag/move a couple of files using sftp: (KIO) and it averaged around 35 Mbytes/sec. KIO in this case is basically unusable, except for small files. I mean, the cost of moving large files taking 3 times longer is not worth the convenience of an easy drag n drop GUI operation. Looking forward to using Kf5 5.53!

BTW when are we ever going to see a kio_rsync slave?

[flower]

I wish they would replace kio with something fuse based

[markg85]

With NFS 1Gbit eth0 to another laptop I can get up to 110 Mbytes/sec transfer speed when I use rsync over NFS between the 2 machines. Last night I thought I'd try Dolphin and drag/move a couple of files using sftp: (KIO) and it averaged around 35 Mbytes/sec. KIO in this case is basically unusable, except for small files. I mean, the cost of moving large files taking 3 times longer is not worth the convenience of an easy drag n drop GUI operation. Looking forward to using Kf5 5.53!

BTW when are we ever going to see a kio_rsync slave?

Read my comment (2 above yours).
Your case is going to stay exactly as is.
Your case needs fixes in the KIO NFS slave. But what those fixes are for optimal performance (same story in the SMB slave) is very difficult to find out. Your patches for fixing that are most welcome!

Also, how do you envision a "kio_rsync" to work? From a dolphin point of view that is. I'm curious to know as the standard file browsing UI will not work for that. Lastly, don't even for a second, assume that a hypothetical "kio_rsync" is all of a sudden going to fully saturate your gigabit network. Getting it working is the easy part, getting it to perform at peek efficiency is darn near impossible.

[markc]

how do you envision a "kio_rsync" to work?

It would be a stretch but grsync provides an ugly GUI frontend to rsync. Select source folder and "copy", select destination folder and "paste" (or drag n drop etc) and the parameters get passed to the rsync executable just like with grsync which also allows for individual files to be sync'd to destination folders.

[markg85]

It would be a stretch but grsync provides an ugly GUI frontend to rsync. Select source folder and "copy", select destination folder and "paste" (or drag n drop etc) and the parameters get passed to the rsync executable just like with grsync which also allows for individual files to be sync'd to destination folders.

I think you would be better off by making a separate rsync gui that can also use KIO slaves. The rsync would be much more dynamic in support as it could access everything KIO can. A "kio_rsync" aplication (or even library) would make sense in that case. But in Dolphin? .. To me that seems (far) outside the scope of file management. You would be in the corner cases area where i doubt many users would use rsync.

Again, you can make patches and see where it ends up