Re: preempt-rt, need old style rwlocks for systemtap

["Frank Ch. Eigler" <fche@redhat.com>]

Hi -

On Sat, May 03, 2008 at 09:34:16AM -0500, Clark Williams wrote:
> [...]
> > It has come to my attention that the preempt-rt patch suite
> > deliberately defeats the potential concurrency intended by systemtap's
> > use of rwlocks to permit concurrent readers [...]

> The reason it "defeats" the concurrent behavior is that it's really
> complicated to have concurrent readers with Priority Inheritance, so
> the initial cut of rtmutexes serialized all lock accesses. [...]

Do you believe priority inheritance to be an essential property of
every use of these primitives, regardless of the nature of the
specifical critical sections being protected?  Is there no way & need
to opt out of the extra machinery?

- FChE