DCEthreads (was Re: Pools in threads)

[Aaron Bannert <aa...@ebuilt.com>]

On Mon, Jul 16, 2001 at 09:05:40AM +0200, Sander Striker wrote:
> > On Mon, Jul 16, 2001 at 01:54:14AM +0200, Luke Kenneth Casson 
> > Leighton wrote:
> > > ah, yes, but it _is_ supported by DCEthreads - see
> > > http://sourceforge.net/projects/freedce which provides,
> > > horror-of-horrors, thread cancellation *emulated* on
> > > top of POSIX threads.
> > [snip, snip]
> > > ... but what i am basically saying is, on NT and Unix,
> > > thread cancellation _is_ possible, it's just that i
> > > think you might not be too happy about the coding-route
> > > you might have to take to _do_ it :) :)
> > 
> > Possible, but not robust.  
> 
> DCE/RPC is _very_ robust. That being the case its underlying
> mechanisms are very likely to be robust too.
> 
> > And, it would add 3.5 million lines of code to APR.  
> 
> Nah. It would add the lines to add thread cancellation.  The
> 3.5 million LOC is the _entire_ dce rpc codebase. Only part
> of that is the dce threads library. And, I believe there are
> some old dce/rpc team members in our midst who could know how
> this all fit together. I could be wrong though.

[warning: tangent -- i changed the subject appropriately]

I must admit that it sounds tantalizing, but I have a comment and a
question:

- It appears that the Free DCE package quoted above is under the GPL
  and is therefore incompatible with the Apache License.

- What is meant by "*emulated* on top of POSIX threads"? What are the
  tradeoffs, if any, compared to a implementation that is native to
  the OS?

-aaron

RE: DCEthreads (was Re: Pools in threads)

[Sander Striker <st...@apache.org>]

>>> And, it would add 3.5 million lines of code to APR.  
>> 
>> Nah. It would add the lines to add thread cancellation.  The
>> 3.5 million LOC is the _entire_ dce rpc codebase. Only part
>> of that is the dce threads library. And, I believe there are
>> some old dce/rpc team members in our midst who could know how
>> this all fit together. I could be wrong though.
> 
> [warning: tangent -- i changed the subject appropriately]
> 
> I must admit that it sounds tantalizing, but I have a comment and a
> question:
> 
> - It appears that the Free DCE package quoted above is under the GPL
>   and is therefore incompatible with the Apache License.

Yes.  However, I wasn't suggesting using or copying code from the
free dce package.  You can merely examine it and decide whether
implementing thread cancellation in such a way is something we want
in APR.  Then, you write your own implementation.

Furthermore, I would like to compare the Free DCE threads implementation
with the DCE/RPC threads implementation.  Then pick the best design
decisions from both.

> - What is meant by "*emulated* on top of POSIX threads"? What are the
>   tradeoffs, if any, compared to a implementation that is native to
>   the OS?

Sander