Re: [lc-devel] Statistics: 0.21

[Rodrigo S. de C. <rc...@im...>]

Hi Paolo,

On Mon, Feb 11, 2002 at 10:10:12AM +0100, CIARROCCHI Paolo wrote:
> My laptop is a HP Omnibook 6000 with 256 Mb RAM, running a 2.4.17
> stock kernel.

Cool.

> I have downloaded the Fillmem/Mmap001, tomorrow I will apply your
> patch.

Just don't test intensively manual adaptivity using 0.22pre2, there a
number of issues related to concurrency that I already fixed. A new
0.22pre3 will be available today or tomorrow.

> Now, my questions:
> + How many compressed cache I have to configure and how I can do it?

You can configure compressed cache initial size in kernel config
options (in make config/menuconfig/xconfig). Another option is to use
the kernel parameter in the boot time.

For example, starting the kernel image with compsize=4096 will boot
the Linux kernel with a compressed cache of 16 MiB. 

Notice that the unit used to configure the compressed cache size is
number of memory pages. Recall that a memory page in i386 is 4096
bytes.

> + What kind of test can I run? Mmap001 300 should be ok?

You can test fillmem or mmap001 using a value at least near to fill
all memory. If you have 256, a range of values from 200-350 would be
nice to test. You can do it in steps of 10, 20, 30 MiB (it's up to
you).

It would also be great if you could test something closer to a normal
workload. For example, loading the same set of programs and then
measure the time taken to execute a program (eg. to load netscape
browser). If you have some idea of a usual workload for you, it would
be great to devise some sort of test to know how well the compressed
cache could be helping this scenario.

Oh, try to gather the compression statistics too (cat
/proc/comp_cache_stat) after your tests. I forgot to do that when run
the last tests.

> If you could point me in the direction to look, I will perform a few
> test using my laptop.

Thank you very much for the help!

Regards,
-- 
Rodrigo S. de Castro <rc...@im...>