Constantin Teodorescu wrote:
> Hello all,
>
> I'm testing jdk 1.2 pre-v1 on my RedHat 5.2 i386 system (64 Mb RAM)
>
> I'm checking the memory footprint of the java machine with 'top'...
It's not as bad as it looks. On Linux, kernel threads take up their own entries
in the process table. Those five entries you see are five threads of the same
process: that 70MB is being shared among all of those threads -- you're not
using 350MB!
OTOH, when you run with green threads, you're using user-space threads, which
the kernel doesn't know about and which don't clutter the process table.
As for the difference between JDK1.1.7 (4MB) and JDK1.2 (70MB)... well, the JRE
has grown a lot, and I also suspect the initial heap size might be larger. I
don't know if that explains everything. Keep in mind that the numbers shown in
the "SIZE" column of "top" are virtual memory -- that's how much address space
you've claimed. You may not need most of that space most of the time; if your
system has swap space available and some other process needs memory, you'll
probably find that most of that memory spends most of its time paged out (you'll
see a much smaller number in the RSS column than the SIZE column).
> I'm checking the memory footprint of the java machine with 'top' in
> another xterm window running a simple program that make some simple math
> calculations, for loops, string and hashtable operations , i.e. nothing
> graphical.
>
> When I am running the program, five (5) 'java' programs are displayed
> by 'top' program, each of them taking 70Mb of RAM !!!!
> When I am running the same program but with -green option, a single
> 'java' program is displayed, with the same 70 Mb of memory footprint
> reported.
>
> The same program under jdk 1.1.7 takes only 4 Mb of RAM !
>
> Does this information helps someone? That behaviour is normal ? It's
> just a debugging phase ?
>
> Anyhow, I was happy to discover that jdk1.2 finishes my little program 3
> (three) times faster than jdk 1.1.7 and in approx. the same time as jdk
> 1.1.7 + TYA 1.3
>
> Best regards,
> --
> Constantin Teodorescu
> FLEX Consulting Braila, ROMANIA
>
>
> ----------------------------------------------------------------------
> To UNSUBSCRIBE, email to [EMAIL PROTECTED]
> with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
>
---------------------------------------------
This message was sent using Endymion MailMan.
http://www.endymion.com/products/mailman/
----------------------------------------------------------------------
To UNSUBSCRIBE, email to [EMAIL PROTECTED]
with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
