Gentoo Archives: gentoo-user

From: Dale <rdalek1967@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] KDE plasmashell and wallpapers.
Date: Tue, 24 Dec 2019 21:23:53
In Reply to: Re: [gentoo-user] KDE plasmashell and wallpapers. by Wols Lists
1 Wols Lists wrote:
2 > On 24/12/19 18:35, Dale wrote:
3 >> I'll try to see if I can get the actual error here in a bit, either a
4 >> picture or the actual text. I only need one line because it is the same
5 >> for them all except the name and path of the file.
6 > I've just had an idea ...
7 >
8 > I think it was on LWN they were talking about how a directory scan on
9 > linux can take absolutely ages, because as it goes through it pulls
10 > everything into cache and knackers the system. (Which is why a lot of
11 > programs go through the grief of using direct rather than buffered io.)
12 >
13 > Not sure which developer it was, but they've brought in a new mode which
14 > leaves cache untouched (sort of). If it can retrieve the file from
15 > cache, it does so. If it's not in cache, it pulls it in, processes it,
16 > and drops it. That way the cache does not fill up with recently accessed
17 > files that are never going to be touched again, and your system doesn't
18 > start swapping like mad to save all this unwanted data.
19 >
20 > Maybe when that is enabled in plasmashell it'll fix the problem ... how
21 > big is this directory that's being scanned? If it's similar or larger in
22 > size to your ram that could be the problem. Even if it's rather less, if
23 > other programs are using up your ram ...
24 >
25 > Cheers,
26 > Wol
27 >
28 >
31 I found out something else.  In the old KDE3 days, it would start at
32 login at the top directory and work its way down while remember the last
33 image.  If you logout and back in, it picks up where it left off at. 
34 KDE5 does something totally different.  It scans every file and puts
35 them in order by the name no matter what directory they are in.  In
36 other words, if I have 100 directories with a image named 0000.jpeg,
37 then it will show the images named 0000.jpeg regardless of what
38 directory they are in.  When that is done, it then moves to say 0001.jpeg. 
40 How did I notice this you ask??  When I added a larger directory, I
41 noticed it did a preview thing in another part of the dialog window.  It
42 also has a little checkbox to disable/enable that image.  What I noticed
43 was what I posted above, how it was putting the images in order.  It
44 just so happens that folder had some slideshow type images in it that
45 are numbered in sequence.  Thing is, in the preview they were all
46 clumped together but were mixed up and not sorted by the directory they
47 were in.  I hate to say it but it is the same result as random done this
48 way. 
50 So, it appears what several of you came up with is correct.  It is
51 building some sort of index/cache/whatever system to organize the
52 images.  That results in a lot of CPU time.  The only question left, if
53 I were to allow it to build that index/whatever, does it rebuild at each
54 login or not??
56 I wonder, if I add each directory within wallpapers a few at a time if
57 it would be workable.  Would it build that index/whatever without
58 locking up?  Even if that works, would it then shows slideshow type
59 directories in sequence or would it still jump to other directories? 
61 Find one possible answer and end up with more questions.  ROFL 
63 Dale
65 :-)  :-)