[RFC] Performance improvements

Swen Schillig swen at vnet.ibm.com
Mon Jul 16 06:51:09 UTC 2018


Hi Andrew

Thanks for your comments, htey're really appreciated.

On Sat, 2018-07-14 at 10:58 +1200, Andrew Bartlett wrote:
> On Fri, 2018-07-13 at 12:56 +0200, Swen Schillig via samba-technical
> wrote:
> > Hi Martin
> > 
> > back from hol's.....see'ing that you won't let go :-)
> > Thanks for that !
> > 
> > On Mon, 2018-07-02 at 16:49 +1000, Martin Schwenke wrote:
> > > 
> > > The tevent programming model is to have an event handler do a
> > > small
> > > amount of work and go back to the event loop.  When you use
> > > immediate
> > > events you definitely give those events an advantage.  However,
> > > that
> > > doesn't mean that you should throw out the programming model.
> > 
> > Ok, I guess I do understand what you call the tevent-programming-
> > model, 
> > but in that code area we only have immediate events making it quiet
> > questionable to me to use it all (therefore patch-10).
> > In addition I do believe that the tevent overhead in this area is
> > noticeable (bold statement w/o any prove).
> 
> G'Day Swen,
> 
> I've not looked at the code in question, but I do want to say this:
> 
> Samba is all about patterns.  Even when we don't like it, we try to
> follow the same patterns because it makes it easier to transition
> from
> one area of the codebase to another, and to glue things together. 
> 
> For example, GENSEC has become our standard security subsystem, even
> when it feels overkill, because it allows us to use new security
> mechanisms easily and enforce a consistent behaviour across the whole
> tree.
> 
> Talloc isn't always needed, and one might feel a desire to fall back
> to
> 'good old malloc()' when 'I know' it is right, but we persist.  In
> return we have good tools for tracing talloc trees and
> avoiding/finding
> lost memory. 
> 
> tevent still baffles me, but we do use it, so please have more of an
> argument than 'we don't really need it', because you might be cutting
> out a future improvement or traceability written for this generic
> framework. 
> > 
> > Thanks,
> > 
> > Andrew Bartlett
> > 
Regarding tevent, I wasn't trying or planning to get rid of it at all.
Believe or not, I think it is very useful.
However, the area of the current discussion is small-ish and
manageable, I think and I was wondering if it is useful to do it the
way it is done.
...so a bit like having your project manager creating only sev-1 tasks.

Anyway, as stated in a reply to Martin, I will let that one (patch) go
for now and focus on the more important ones.

Thanks.

Cheers Swen.




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