[parsec-users] Scalability of PARSEC benchmarks ?

Roberto Giorgi giorgi at dii.unisi.it
Tue Apr 1 16:02:24 EDT 2008

Hi Chris,
... so you mean that if I have perfect memory and perfect
interconnection network,
then there is no bottlneck in the applications (or at least the serial
portions are minimal) ?



Hello Roberto,

How well the PARSEC workloads scale in practice depends on the machine. All
programs scale well to a large number of cores if their requirements are met.
In practice (or if you simulate a realistic machine) you will frequently hit
memory bandwidth limitations soon.

If you only care about good scalability start with programs that have small
working sets first. Depending on your architecture intense communication
between threads can consume a lot of memory bandwidth, too. The commercial
workloads which use the pipeline model tend to be tougher on the machine in
that sense.

The more your workloads have those two properties (large working sets &
intense communication) the more challenging it will be to achieve good
speedups. Have a look at the characterization to get an impression of the
requirements of PARSEC programs.

- Chris

On Tuesday 01 April 2008 07:03 am, Roberto Giorgi wrote:
> Hi, I'm new to PARSEC: can someone please tell me if these benchmarks
> can be used in scalbility studies, e.g. at least up to 64-128 cores (like
> SPLASH-2)?
> In case of positive answer: which benchmark could I first start with
> (simpler, more scalable with number of cores)?
> Thanks!
> Roberto.

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