Re: [PATCH bpf-next] verifier: add prune points to live registers print

[Eduard Zingerman <eddyz87@gmail.com>]

On Tue, 2025-12-30 at 17:11 -0800, Alexei Starovoitov wrote:
> On Tue, Dec 30, 2025 at 10:44 AM Eduard Zingerman <eddyz87@gmail.com> wrote:
> > 
> > > 
> > > that will make post processing easier, but print on every miss
> > > will greatly increase log_level=2 size, right ?
> > 
> > Here are some stats for pyperf180:
> > 
> > > Experiment                                  | Log   | Log  |
> > > Kind                                        | Lines | Size |
> > > ---------------------------------------------+-------+------|
> > > Print cache hits, misses and diffing values | 626K  | 88M  |
> > > Print cache misses and diffing values       | 618K  | 88M  |
> > > Print cache misses                          | 618K  | 87M  |
> > > Default level 2 log                         | 577K  | 85M  |
> 
> hmm. That's not that much.
> Then I don't understand why you said:
> "slows down log level 2 output significantly (~5 times)"
> 
> If the total output is roughly the same, how come it's 5 times slower??

That's an interesting question.
Double checked the log for the failing program I was debugging
(internal, hits 1M limit): 6M lines total, 1.4M lines are "cache ...",
so 20% instead of 8% for pyperf180.
Still does not explain the performance difference.
I'll check what happens using profiler.