Re: Copying files slows X GUI to molasses
- From: Jan Wielemaker <jan@xxxxxxxxxxxxxxxxxxx>
- Date: 29 Mar 2006 08:09:55 GMT
On 2006-03-29, AA <AA@xxxxxxxxxxx> wrote:
Jan Wielemaker wrote:
On 2006-03-28, Segin <segin2005@xxxxxxxxx> wrote:
I'm running Ubuntu 5.10 (kde) on my Thinkpad T42. If I mount a cdrom
and copy the files to my internal HDD the GUI slows way down and is very
sluggish. I guess I must have something misconfigured. Any suggestions
on where to look? I am completely clueless when it comes to this type
you're probably running out of RAM, get more RAM
I think it is much more fundamental. Copying large files (meaning
comparable to the size of physical memory) has very serious performance
implications for interactive applications because the file copy eats
cached pages. As, apart from the copying, there isn't going to be any
reuse, this is pretty bad for performance, especially for people like me
that assume that money spend on more memory is better spend than money
spend on faster discs. So, I've got 2GB memory, but while copying
multiple GB files, the system is barely useable.
Somehow the ssytem should recognise the pattern and stop eating general
file buffering if a big copy/write is in progress.
Cheers --- Jan
I've got 1GB of memory. I think it's a 5400 RPM HDD. I guess I can
understand the idea of file paging, but if all I am doing it moving the
cursor across the screen this should require no disk access, right?
Even just moving the cursor causes applications that get/loose focus
or wish to provide feedback on the cursor location to do work. I
_think_ the trouble is that the disc copy uses pages from executables
for disc cache, so the system needs to re-fetch these pages if you
start using the executable again. Same happens here if my system is
recording TV (basically copying from PVR card to a file at a rate of
about 4GB/hour). Applications I'm using work just fine, but if I
switch to applications I've not been using for a while the app starts
to respond slowly. Same for the whole desktop if I leave the system
alone for say 30 minutes. I can only explain that by assuming the
copy from TV device to HDD is using pages from executables (swap is
almost 0). There is really no point in this. The data should go
to HDD as soon as possible and the cache page should be the first
to reuse after the data is written to HDD.
Perhaps this is important: I was copying the files from a DVD+R in my.
local DVD drive to my local HDD. I wonder if that is significant.
Although I haven't tested it recently, I don't recall this slow down
ever happening in Windows, that's why I believe it is a software not a
hardware config problem.
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