[PATCH] Enhance time sampling of async IO VFS functions

[Ralph Boehme]

On Sun, Feb 28, 2016 at 11:28:06AM +0100, Volker Lendecke wrote:
> On Fri, Feb 26, 2016 at 09:56:58PM +0100, Ralph Boehme wrote:
> > On Fri, Feb 26, 2016 at 10:45:31AM -0800, Jeremy Allison wrote:
> > > On Fri, Feb 26, 2016 at 06:39:36PM +0100, Ralph Boehme wrote:
> > > > I though about adding struct tevent_req.async.(uint64_t)duration and
> > > > getter/setter functions
> > > > tevent_req_set_duration()/tevent_req_get_duration().
> > > > 
> > > > This could then be used by the implementation of an async request to
> > > > set the duration and the caller can read it, further passing up the
> > > > stack and processing as needed.
> > > 
> > > If we want to make this a generic feature of tevent, then
> > > the above is the way to go - but I think that needs a bigger
> > > discussion than just you and I.
> > > 
> > > Metze, Volker - what do you think about adding duration
> > > as a feature to tevent_req.async ?
> > 
> > something like this.
> 
> Is it theoretically possible to implement this feature without modifying
> tevent, ...

yes.

> ... just within asys.c?

No.

We need to somehow pass the info to and up the VFS stack, but this can
also be achieved by modifying the aio VFS funcs args, as mentioned
before.

-Ralph

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