[mythtv-users] Will moving to DDR-400 memory from DDR-333 improve performance?

[Chris Pinkham]

* On Mon Oct 30, 2006 at 09:13:45PM -0500, Brian J. Murrell wrote:
> > USER       PID %CPU %MEM   VSZ  RSS TTY      STAT START   TIME COMMAND
> > mythtv    2074  0.1 11.8 248100 30244 pts/2  S    Oct28   3:27 mythbackend
>                            ^^^^^^ ^^^^^
> Uhm, these are in KiB you realize yes?

Obviously, that's why I said this: :)

> > OK, so we're using ~30MB there for mythbackend.

You see, kilobytes * 1024 == megabytes.

> > Just because the VSZ of a program is 260MB doesn't mean it's using that,
> 
> Any one time, yes, you are correct.  But that that much of the process
> is sitting out in swap just means there is going to be a lot of disk
> thrashing when the process does need it.

If Myth is using the code then it will stay in memory.  You're saying that
Linux is swapping out program code in order to keep the filesystem cache
large which isn't true unless theres some big unknown bug out there.  Or
maybe you're thinking that all the GUI code in the Qt libraries is going
to suddenly need to be swapped into memory while mythbackend is running.

> disk when the portions of "code" that are not in memory are executed.
> Whether it has to come from swap or from the filesystem really, makes no
> difference in the effect.

Most of it will never need to be read from anywhere so the VSZ number
is meaningless.

--
Chris