<s>
The	O
Parallel	O
Multithreaded	O
Machine	O
(	O
PM2	B-Application
)	O
is	O
a	O
software	O
for	O
parallel	O
networking	O
of	O
computers	O
.	O
</s>
<s>
PM2	B-Application
is	O
an	O
open-source	O
distributed	O
multithreaded	B-Operating_System
programming	I-Operating_System
environment	O
designed	O
to	O
support	O
efficiently	O
distributed	B-Architecture
programs	I-Architecture
with	O
a	O
highly	O
irregular	O
behavior	O
(	O
e.g.	O
</s>
<s>
branch	B-Algorithm
and	I-Algorithm
bound	I-Algorithm
search	O
,	O
computation	O
on	O
sparse	B-Algorithm
matrices	I-Algorithm
,	O
etc	O
.	O
)	O
</s>
<s>
It	O
is	O
distributed	O
under	O
the	O
GPL	B-License
.	O
</s>
<s>
PM2	B-Application
adheres	O
to	O
the	O
SPMD	O
(	O
Single	O
Program	O
Multiple	O
Data	O
)	O
programming	O
model	O
,	O
in	O
a	O
way	O
very	O
similar	O
to	O
the	O
PVM	B-Operating_System
and	O
MPI	O
communication	O
libraries	O
.	O
</s>
<s>
This	O
way	O
it	O
allows	O
a	O
network	O
of	O
heterogeneous	O
machines	O
to	O
be	O
used	O
as	O
a	O
single	O
distributed	O
parallel	B-Operating_System
processor	I-Operating_System
.	O
</s>
<s>
It	O
is	O
primarily	O
designed	O
for	O
medium-size	O
clusters	O
of	O
commodity	O
processing	O
nodes	O
interconnected	O
by	O
high-performance	O
networks	O
,	O
but	O
nothing	O
prevents	O
the	O
use	O
on	O
massively	O
parallel	O
MIMD	B-Operating_System
machines	O
at	O
one	O
end	O
of	O
the	O
spectrum	O
,	O
or	O
as	O
a	O
support	O
for	O
metacomputing	B-Device
over	O
the	O
Internet	O
on	O
the	O
other	O
end	O
.	O
</s>
<s>
Distinguishing	O
features	O
of	O
PM2	B-Application
include	O
its	O
priority	O
driven	O
scheduling	O
policy	O
,	O
its	O
thread	B-Operating_System
migration	O
mechanisms	O
and	O
its	O
ability	O
to	O
ease	O
the	O
development	O
of	O
various	O
load	O
balancing	O
policies	O
.	O
</s>
<s>
It	O
can	O
manage	O
several	O
hundreds	O
of	O
threads	B-Operating_System
on	O
each	O
available	O
physical	O
processor	O
.	O
</s>
<s>
The	O
PM2	B-Application
interface	O
provides	O
functionalities	O
for	O
the	O
management	O
of	O
this	O
high	O
degree	O
of	O
parallelism	B-Operating_System
and	O
for	O
dynamic	O
load	O
balancing	O
.	O
</s>
<s>
The	O
thread	B-Operating_System
management	I-Operating_System
subsystem	O
of	O
PM2	B-Application
is	O
called	O
Marcel	O
(	O
named	O
after	O
Marcel	O
Proust	O
)	O
and	O
its	O
communication	O
subsystem	O
Madeleine	O
,	O
a	O
French	O
sweet	O
that	O
supposedly	O
played	O
a	O
central	O
role	O
in	O
the	O
life	O
of	O
Marcel	O
Proust	O
.	O
</s>
<s>
PM2	B-Application
features	O
an	O
additional	O
functionality	O
to	O
provide	O
threads	B-Operating_System
with	O
a	O
uniform	O
access	O
to	O
data	O
,	O
whatever	O
their	O
physical	O
location	O
.	O
</s>
<s>
It	O
is	O
called	O
DSM-PM2	O
.	O
</s>
<s>
PM2	B-Application
runs	O
on	O
most	O
Unix	B-Application
platforms	O
.	O
</s>
<s>
PM2	B-Application
is	O
developed	O
at	O
LaBRI	O
(	O
Laboratoire	O
Bordelais	O
de	O
Recherche	O
en	O
Informatique	O
)	O
,	O
a	O
research	O
laboratory	O
located	O
in	O
Bordeaux	O
,	O
France	O
,	O
jointly	O
supported	O
by	O
the	O
INRIA	O
,	O
the	O
CNRS	O
,	O
and	O
the	O
University	O
of	O
Bordeaux	O
.	O
</s>
<s>
Before	O
that	O
,	O
PM2	B-Application
was	O
developed	O
at	O
LIP	O
(	O
Laboratoire	O
de	O
l'Informatique	O
du	O
Parallélisme	O
)	O
,	O
a	O
research	O
laboratory	O
located	O
at	O
the	O
ENS	O
Lyon	O
(	O
Ecole	O
Normale	O
Supérieure	O
de	O
Lyon	O
)	O
,	O
France	O
,	O
jointly	O
supported	O
by	O
the	O
INRIA	O
,	O
the	O
CNRS	O
and	O
the	O
University	O
Claude	O
Bernard	O
Lyon	O
.	O
</s>
<s>
PM2	B-Application
was	O
originally	O
designed	O
by	O
Raymond	O
Namyst	O
and	O
Jean-François	O
Méhaut	O
at	O
LIFL	O
,	O
University	O
of	O
Lille	O
,	O
France	O
.	O
</s>
