From: Eduard Zingerman <eddyz87@gmail.com>
To: Nandakumar Edamana <nandakumar@nandakumar.co.in>
Cc: bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Jakub Sitnicki <jakub@cloudflare.com>,
Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Subject: Re: [PATCH v4 bpf-next 1/2] bpf: improve the general precision of tnum_mul
Date: Mon, 25 Aug 2025 08:51:39 -0700 [thread overview]
Message-ID: <1c293ea48cfb4a0852570517b9daf155a2a3bde4.camel@gmail.com> (raw)
In-Reply-To: <0ed1ad1d73d2c4468b3a02b3034b7dfd6e693d66.camel@gmail.com>
On Fri, 2025-08-22 at 16:56 -0700, Eduard Zingerman wrote:
> On Sat, 2025-08-23 at 05:18 +0530, Nandakumar Edamana wrote:
>
> [...]
>
> > I personally don't think `best(a*b, b*a)` is ugly. What about
> > `best(oldprod, newprod)`, where oldprod and newprod are each found
> > like this, using the old tnum_mul and the new tnum_mul respectively?
>
> Hm, given that both are correct if we go for a hybrid approach we can
> peek known bits from both.
Thinking it over the weekend, I tend to agree with Harishankar.
Few percent improvement does not merit complications with best part
selection or maintaining two algorithms for multiplication.
I'd stick with the new algorithm as in the current patch.
next prev parent reply other threads:[~2025-08-25 15:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-22 17:08 [PATCH v4 bpf-next 1/2] bpf: improve the general precision of tnum_mul Nandakumar Edamana
2025-08-22 17:08 ` [PATCH v4 bpf-next 2/2] bpf: add selftest to check the verifier's abstract multiplication Nandakumar Edamana
2025-08-22 18:59 ` Eduard Zingerman
2025-08-22 18:37 ` [PATCH v4 bpf-next 1/2] bpf: improve the general precision of tnum_mul Eduard Zingerman
2025-08-22 18:58 ` Nandakumar Edamana
2025-08-22 21:14 ` Harishankar Vishwanathan
2025-08-22 21:50 ` Eduard Zingerman
2025-08-22 23:48 ` Nandakumar Edamana
2025-08-22 23:56 ` Eduard Zingerman
2025-08-25 4:16 ` Nandakumar Edamana
2025-08-25 16:24 ` Eduard Zingerman
2025-08-25 16:56 ` Nandakumar Edamana
2025-08-25 16:57 ` Eduard Zingerman
2025-08-25 15:51 ` Eduard Zingerman [this message]
2025-08-22 23:50 ` Harishankar Vishwanathan
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