Re: [PATCH v5 06/13] lockdep: Implement crossrelease feature

Byungchul Park
2017-03-05T03:34:15Z

On Fri, Mar 03, 2017 at 10:13:38AM +0100, Peter Zijlstra wrote:
> On Fri, Mar 03, 2017 at 09:14:16AM +0100, Peter Zijlstra wrote:
>
> Two boots + a make defconfig, the first didn't have the redundant bit
> in, the second did (full diff below still includes the reclaim rework,
> because that was still in that kernel and I forgot to reset the tree).
>
>
> lock-classes: 1168 1169 [max: 8191]
> direct dependencies: 7688 5812 [max: 32768]
> indirect dependencies: 25492 25937
> all direct dependencies: 220113 217512
> dependency chains: 9005 9008 [max: 65536]
> dependency chain hlocks: 34450 34366 [max: 327680]
> in-hardirq chains: 55 51
> in-softirq chains: 371 378
> in-process chains: 8579 8579
> stack-trace entries: 108073 88474 [max: 524288]
> combined max dependencies: 178738560 169094640
>
> max locking depth: 15 15
> max bfs queue depth: 320 329
>
> cyclic checks: 9123 9190
>
> redundant checks: 5046
> redundant links: 1828
>
> find-mask forwards checks: 2564 2599
> find-mask backwards checks: 39521 39789
>
>
> So it saves nearly 2k links and a fair chunk of stack-trace entries, but

It's as we expect.

> as expected, makes no real difference on the indirect dependencies.

It looks that the indirect dependencies increased to me. This result is
also somewhat anticipated.

> At the same time, you see the max BFS depth increase, which is also

Yes. The depth should increase.

> expected, although it could easily be boot variance -- these numbers are
> not entirely stable between boots.
>
> Could you run something similar? Or I'll take a look on your next spin
> of the patches.

I will check same thing you did and let you know the result at next spin.