* Byungchul Park <[email protected]> wrote:
> On Thu, Oct 19, 2017 at 07:57:30AM +0200, Ingo Molnar wrote:
> >
> > * Byungchul Park <[email protected]> wrote:
> >
> > > On Wed, Oct 18, 2017 at 12:09:44PM +0200, Ingo Molnar wrote:
> > > > BTW., have you attempted limiting the depth of the stack traces? I
> > > > suspect more
> > > > than 2-4 are rarely required to disambiguate the calling context.
> > >
> > > I did it for you. Let me show you the result.
> > >
> > > 1. No lockdep: 2.756558155 seconds time
> > > elapsed ( +- 0.09% )
> > > 2. Lockdep: 2.968710420 seconds
> > > time elapsed ( +- 0.12% )
> > > 3. Lockdep + Crossrelease 5 entries: 3.153839636 seconds
> > > time elapsed ( +- 0.31% )
> > > 4. Lockdep + Crossrelease 3 entries: 3.137205534 seconds
> > > time elapsed ( +- 0.87% )
> > > 5. Lockdep + Crossrelease + This patch: 2.963669551 seconds time
> > > elapsed ( +- 0.11% )
> >
> > I think the lockdep + crossrelease + full-stack numbers are missing?
>
> Ah, the last version of crossrelease merged into vanilla, records 5
> entries, since I thought it overloads too much if full stack is used,
> and 5 entries are enough. Don't you think so?
Ok, fair enough, I missed that limitation!
> > That's very reasonable and we can keep the single-entry cross-release
> > feature
> > enabled by default as part of CONFIG_PROVE_LOCKING=y - assuming all the
> > crashes
>
> BTW, is there any crash by cross-release I don't know? Of course, I know
> cases of false positives, but I don't about crash.
There's no current crash regression that I know of - I'm just outlining the
conditions of getting all this re-enabled in the next merge window.
Instead of sending two series, could you please send a series that includes
both
these fixing + re-enabling patches, plus the false positive fixes?
In particular I think the cross-release re-enabling should be done as the last
patch, so that any future bisections of new false positives won't be made more
difficult by re-introducing the old false positives near the end of the
bisection.
Thanks,
Ingo
