On Wed, 9 Feb 2000, Jeff Waller wrote:
> I noted that the kernel I am currently using 2.2.14 + DVD patches
> preformed poorly when attempting to play DVD's. Poorly in that the
> Xerver becomes unresponsive to mouse motion, remote logins hang.
> The disk goes crazy, basically, I think the system is thrashing.
Very much likely. Virtual memory in 2.2 sucks. We hope to have
it mostly fixed in 2.2.15 (current prepatch level pre-7, get it
from ftp://ftp.kernel.org/pub/linux/kernel/people/alan/).
I'd like to hear how that prepatch performs for you. If it
still sucks in certain situations I'll see what I can do...
> It appeared that Xwindows without the DVD-related software
> running (or ever having run) takes about 55 M.
The critical word here is "appeared". The X server usually maps
in all the video card memory and a half-dozen libraries. All of
those count towards the size of the program, even though not
all of them are memory resident.
> But afterwords, top reports an anomalous amount of memory
> being used. Apparently by the kernel...Apparently. As a test
> I tried (after rebooting)
>
> find /dvd -type f -exec cat {} > /dev/null \;
>
> Thinking that perhaps the kernel was allocating memory but
> not releasing it and in fact all free memory was "used up"
> at least by what top reports.
The kernel keeps disk buffers around, freeing them when
memory is needed again. Free memory is wasted memory...
(mainly because reading things in from disk is about
100.000 times slower than reading from RAM and we can
free the memory fast enough when we need it again)
> Could you suggest where I can delve deeper? Is this a
> known problem?
It's a known problem and we hope to have solved it in
kernel version 2.2.15.
regards,
Rik
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This archive was generated by hypermail 2b29 : Tue Feb 15 2000 - 21:00:15 EST