[gclist] Real-Time GC for high-level languages

Francois-Rene Rideau fare@tunes.org
Tue, 30 Jan 2001 19:48:29 +0100

On Tue, Jan 30, 2001 at 09:48:26AM -0800, Jim Larson wrote:
> The Open-Source Erlang implementation achieves soft real-time GC [...]
> The Erlang GC may exhibit chronic pauses if too much data is live
> in a single process.  However, the Erlang programming style
> discourages this from happening.
Ok. Thanks for the whole explanation (including the snipped part).
In practice, what kind of "soft-real-time" constraints are met by
Erlang-deployed systems? And what impact does management of the shared
data (bulk as well as system management information about processes)
have on the real-time response?

On Tue, Jan 30, 2001 at 12:56:37PM -0500, David Chase wrote:
> Another thing to consider is whether or not there are any constraints
> on the memory-related behavior of the programs that you are running.
> If, for instance, you can tell me that it never has more than X Mb
> of live memory, then I can tell you how long a straightforward
> copying-compacting collection will take (for small sets of data,
> they are fast) after making some measurements.
So that actually this property is not specific to Erlang,
only the Erlang programming style specifically takes advantage of it
in achieving real-time behavior.

> On the other hand, if you've got no constraints on your running
> program, you will find your hard-real-time GC choices exceedingly
> limited.
Assuming this is the case, what does that amount to?

Also are there any high-level language compilers that do automatic
memory management accross several arena, as opposed to just static memory
management accross several arena (as is done in the ML-Kit with region)?
I.e. each arena having a different read/write/lock/allocate/free protocol,
maybe programmably so? I suppose that once again, Erlang, with message
passing accross separate processes, is mostly in that case.

> The FAQ is only slightly maintained.  I will see what I can do about its
> links.  Are you, perhaps, volunteering to help? :-)
Sure, especially since you say you're using CVS.

Thanks to all those who responded and will respond.
Yours freely,

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
[  TUNES project for a Free Reflective Computing System  | http://tunes.org  ]
They laughed at Columbus, they laughed at Fulton, they laughed at the
Wright brothers.  But they also laughed at Bozo the Clown.
		-- Carl Sagan