From: Paul Chaignon <paul.chaignon@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>
Cc: bpf@vger.kernel.org, ast@kernel.org, andrii@kernel.org,
daniel@iogearbox.net, martin.lau@linux.dev, kernel-team@fb.com,
yonghong.song@linux.dev,
Alexei Starovoitov <alexei.starovoitov@gmail.com>
Subject: Re: [PATCH bpf-next v4 09/14] bpf: simplify liveness to use (callsite, depth) keyed func_instances
Date: Mon, 13 Apr 2026 15:31:04 +0200 [thread overview]
Message-ID: <adzwGJXuXcVbF5H1@Tunnel> (raw)
In-Reply-To: <fb4290b261d2265e9cf64cd6f67df9d0e1a1ac74.camel@gmail.com>
On Fri, Apr 10, 2026 at 02:42:53PM -0700, Eduard Zingerman wrote:
> On Fri, 2026-04-10 at 23:39 +0200, Paul Chaignon wrote:
>
> [...]
>
> > I tested this series with Cilium's complexity test suite [1]. We have a
> > lot of different configuration and some producing larger programs than
> > covered in the cover letter.
> >
> > Overall, the impact is quite good. It reduces the number of processed
> > instructions by more than 60k instructions for some of our largest
> > programs. It also increases the number of processed instructions by up
> > to 20k in fewer other cases, but I think it's manageable because they
> > are not the largest programs so we have some room. The mean diff over
> > all programs is a reduction of a few thousands processed instructions.
>
> Hi Paul,
>
> Thank you for testing this series!
> Are the regressing program open-source?
> If so, could you please point to a few?
Hi Eduard,
Yes, all programs tested are from Cilium OSS. [1] shows the overall
results grouped by program (each line covers multiple configurations).
I've uploaded details for programs (a) tail_nodeport_nat_ingress_ipv4
and (b) tail_handle_ipv4_cont with configurations for which your
patchset causes an increase in complexity. The object file at [2]
contains program (a) compiled with the Cilium configuration from [3].
The impact of your patchset on that program is at [4]. For program (b),
see [5, 6, 7].
These programs are quite large so not the easiest to dig into.
Unfortunately, I'm not seeing anything obvious that differentiate the
programs with a positive impact from those with a negative impact.
Don't hesitate if I can do anything to help! I can also share the
verifier logs if that helps.
1: https://pchaigno.github.io/assets/static-liveness-complexity/complexity-results.png
2: https://pchaigno.github.io/assets/static-liveness-complexity/bpf_host-3.o
3: https://github.com/cilium/cilium/blob/12955851fc2f0c25f01d0df27a66c0ed6c275f59/bpf/complexity-tests/netnext/bpf_host/3.txt
4: https://pchaigno.github.io/assets/static-liveness-complexity/bpf_host-build3.png
5: https://pchaigno.github.io/assets/static-liveness-complexity/bpf_lxc-7.o
6: https://github.com/cilium/cilium/blob/12955851fc2f0c25f01d0df27a66c0ed6c275f59/bpf/complexity-tests/netnext/bpf_lxc/7.txt
7: https://pchaigno.github.io/assets/static-liveness-complexity/bpf_lxc-build7.png
>
> [...]
next prev parent reply other threads:[~2026-04-13 13:31 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 20:55 [PATCH bpf-next v4 00/14] bpf: static stack liveness data flow analysis Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 01/14] bpf: share several utility functions as internal API Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 02/14] bpf: save subprogram name in bpf_subprog_info Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 03/14] bpf: Add spis_*() helpers for 4-byte stack slot bitmasks Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 04/14] bpf: make liveness.c track stack with 4-byte granularity Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 05/14] bpf: 4-byte precise clean_verifier_state Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 06/14] bpf: prepare liveness internal API for static analysis pass Eduard Zingerman
2026-04-10 20:55 ` [PATCH bpf-next v4 07/14] bpf: introduce forward arg-tracking dataflow analysis Eduard Zingerman
2026-04-10 21:44 ` bot+bpf-ci
2026-04-10 21:46 ` Eduard Zingerman
2026-04-10 22:17 ` Alexei Starovoitov
2026-04-10 20:55 ` [PATCH bpf-next v4 08/14] bpf: record arg tracking results in bpf_liveness masks Eduard Zingerman
2026-04-10 20:56 ` [PATCH bpf-next v4 09/14] bpf: simplify liveness to use (callsite, depth) keyed func_instances Eduard Zingerman
2026-04-10 21:39 ` Paul Chaignon
2026-04-10 21:42 ` Eduard Zingerman
2026-04-13 13:31 ` Paul Chaignon [this message]
2026-04-10 21:44 ` bot+bpf-ci
2026-04-10 22:33 ` Alexei Starovoitov
2026-04-10 20:56 ` [PATCH bpf-next v4 10/14] bpf: change logging scheme for live stack analysis Eduard Zingerman
2026-04-10 20:56 ` [PATCH bpf-next v4 11/14] selftests/bpf: update existing tests due to liveness changes Eduard Zingerman
2026-04-10 20:56 ` [PATCH bpf-next v4 12/14] selftests/bpf: adjust verifier_log buffers Eduard Zingerman
2026-04-10 20:56 ` [PATCH bpf-next v4 13/14] selftests/bpf: add new tests for static stack liveness analysis Eduard Zingerman
2026-04-10 20:56 ` [PATCH bpf-next v4 14/14] bpf: poison dead stack slots Eduard Zingerman
2026-04-10 22:40 ` [PATCH bpf-next v4 00/14] bpf: static stack liveness data flow analysis patchwork-bot+netdevbpf
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