netdev - Re: [RFC PATCH v2 bpf-next 0/2] verifier liveness simplification

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Date:   Fri, 31 Aug 2018 16:50:11 +0100
From:   Edward Cree <ecree@...arflare.com>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
CC:     <ast@...nel.org>, <daniel@...earbox.net>, <netdev@...r.kernel.org>
Subject: Re: [RFC PATCH v2 bpf-next 0/2] verifier liveness simplification

On 30/08/18 03:18, Alexei Starovoitov wrote:
> I think it's a better base to continue debugging.
> In particular:
> 1. we have instability issue in the verifier.
>  from time to time the verifier goes to process extra 7 instructions on one
>  of the cilium tests. This was happening before and after this set.
I can't reproduce this; I always get 36926.  Can you try recording the
 verifier log and diff the output between the two cases?
> 2. there is a nice improvement in number of processed insns with this set,
>  but the difference I cannot explain, hence it has to debugged.
>  In theory the liveness rewrite shouldn't cause the difference in processed insns.
I shall attack this with the same methods I used for the other delta.
 Since that one turned out to be a real bug in the patch, I'm not so
 sanguine as to dismiss this one as probably connected to issue 1.

-Ed