[bt-devel] Bibletime time required to load vs available memory

[fred]

          [bt-devel] --debug
     Date:
          Mon, 1 Jan 2001 02:48:16 +0100
     From:
          Joachim Ansorg <jansorg@gmx.de>
 Reply-To:
          bt-devel@crosswire.org

I figured out the memory problem that I reported was actually a misconfigured
swap file.  I have completed some testing to find out how much memory
is actually needed.  The results follow.

>From the observation of the computer's behavior, I am going to guess
that the following occurs:

If the size of the files for current use exceed physical ram than the
files are passed to swap.

If the size of the files for current use exceed physical ram and swap,
the kernel attempts to work around by paging between ram and swap.  If
this does not free up sufficiennt memory, then files are dropped from
swap, and are called from the hard drive when needed.

As getting data from an ext2 partition must be processed as it is passed
into ram, this will be slower than a call to swap.  Aparently there are
processor intensive operations for management of paging that also come
into play here.

If this were to occur in windows (including windows NT4) the result is a
"system is running low on resources" error message, followed by a
crash.  In Linux the kernel does not crash but you may have to wait some
time for the process to finish.

Based on information gathered from KDE system guard on my system which
has 32MB physical ram,

                                                              RAM
SWAP      TOTAL
Mandrake 7.2 with KDE open uses                               31600  +
18706  =  50396
Bibletime with all the modules I could load at the same time  31632  +
38524  =  70156

So bibletime requires 19760 kB of memory in addition to the system
process requirements.

A recommendation for system memory requirements that the total of
physical ram and swap should be more than say 80kB.  Note prevously with
my system miss configured bibletime 0.3 was able to load and function
with 32MB of RAM + 32MB Swap (64MB total).  However in this condition
the last module took ~ 15 minutes to load and the disk thrashed
constantly.  After increasing the SWAP file bibletime loads sword
modules quickly even when all of them are open at the same time
(including all of the lexicons).  The loading time for the lexicons is
all about the same, and does not seem to depend on how many (or how
large) other sword modules are loaded.

Best Regards
Fred Saalbach