Re: thousands of CPU cores

[Sylvain Le Gall <sylvain@le-gall.net>]

On 11-07-2008, Jon Harrop <jon@ffconsultancy.com> wrote:
> On Friday 11 July 2008 07:26:44 Sylvain Le Gall wrote:
>> On 10-07-2008, Oliver Bandel <oliver@first.in-berlin.de> wrote:
>
> However, any serious power users will already be on 64-bit where these limits 
> have been relegated to quaint stories your grandpa will tell you.
>

As you cannot ignore people running on Windows, you cannot ignore people
running on older hardware.

If you plan to program a big DB that will use more than 3GB on 32 bits
hardware, you should take care of this memory limit and consider
splitting your application into several process... 

The "process" approach to parallelism:
- is basic but should fit to most OS around
- require work to split application correctly, wrt to require
  communication bandwidth
- cannot take advantage of shared memory (well you CAN share memory, but
  it is not as easy as in thread/single process)
- increase safety by really separating data

I mean, you can get really good performance with threaded app BUT you
have many drawbacks that create weird behavior/undetectable runtime
bugs. Process approach is portable and limit possible bugs to
communication...

Regards,
Sylvain Le Gall