Re: Consensus: data-race freedom as default for glibc code

[Florian Weimer <fweimer at redhat dot com>]

On 11/24/2014 04:45 PM, Torvald Riegel wrote:
> On Mon, 2014-11-24 at 16:25 +0100, Florian Weimer wrote:
> > On 11/24/2014 04:23 PM, Torvald Riegel wrote:
> > > >    >   * Parallel algorithms implemented in glibc itself will be free from
> > > >    >     data races (as defined by C11 and its memory model) by default.
> > >
> > > I changed it to:
> > > * Concurrent code in glibc is free from data races (as defined by C11
> > > and its memory model) by default.
> >
> > Fine with me as well (although I think technically, this is about
> > parallelism, not concurrency :-).
>
> And I disagree, that's why I changed it :)
>
> We don't parallelize anything in glibc.

Ugh, we parallelize the execution of threads (unlike the old FSU threads 
implementation).

> How would you define both categories?

Concurrency is non-deterministic execution of (sequential) subprograms 
in response to external events.  Parallelism is the simultaneous, 
interleaved execution of subprograms.  Or something like thatâbasically, 
you can only have high-level race conditions in a concurrent 
application, for low-level things (covered by the C11 memory model), you 
need parallelism.

But I suspect this particular sub-discussion will never have a fruitful 
outcome.

--
Florian Weimer / Red Hat Product Security