Re: Too many PMC implementations

[christos%zoulas.com@localhost (Christos Zoulas)]

On Aug 23, 11:57am, tls%panix.com@localhost (Thor Lancelot Simon) wrote:
-- Subject: Re: Too many PMC implementations

| On Thu, Aug 23, 2018 at 05:09:35PM +0200, Kamil Rytarowski wrote:
| > 
| > Observing that all the useful profiling is already done with DTrace, we
| > can remove complexity from the kernel with negligible cost.
| 
| I'm not sure what to make of this.  I'm trying to come up with a way to
| make the above statement true, and I'm having some difficulty.
| 
| You can't possibly mean "Observing that (unproven premise), therefore
| (conclusion)", so I'll discard that interpretation.
| 
| Do you perhaps mean "*If* we were to observe that all useful profiling
| were done with DTrace, *then* we could remove complexity from the
| kernel with negligible cost"?
| 
| Because Ragge and others have been pointing out that in that case,
| the premise "all useful profiling is done with DTrace" does not appear
| to be true.  Profiling kernel code on VAX may not be useful *to you*
| but that does not imply it is "not useful" simpliciter.
| 

Until we port dtrace to at least a good representative set of architectures
we should not remove the only means of profiling for the kernel.

christos