netdev - Re: [PATCH bpf-next 0/4] nfp: bpf: optimize negative sums

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Message-ID: <35ea0275-df8c-de0e-6c5b-43053747ada5@iogearbox.net>
Date:   Wed, 25 Apr 2018 09:58:58 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Jakub Kicinski <jakub.kicinski@...ronome.com>,
        alexei.starovoitov@...il.com
Cc:     oss-drivers@...ronome.com, netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next 0/4] nfp: bpf: optimize negative sums

On 04/25/2018 06:22 AM, Jakub Kicinski wrote:
> Hi!
> 
> This set adds an optimization run to the NFP jit to turn ADD and SUB
> instructions with negative immediate into the opposite operation with
> a positive immediate.  NFP can fit small immediates into the instructions
> but it can't ever fit negative immediates.  Addition of small negative
> immediates is quite common in BPF programs for stack address calculations,
> therefore this optimization gives us non-negligible savings in instruction
> count (up to 4%).

Applied to bpf-next, thanks Jakub!