All of lore.kernel.org
 help / color / mirror / Atom feed
From: Daniel Borkmann <daniel@iogearbox.net>
To: Luke Nelson <lukenels@cs.washington.edu>, bpf@vger.kernel.org
Cc: Luke Nelson <luke.r.nels@gmail.com>, Xi Wang <xi.wang@gmail.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Zi Shen Lim <zlim.lnx@gmail.com>, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	Andrii Nakryiko <andriin@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Enrico Weigelt <info@metux.net>, Torsten Duwe <duwe@suse.de>,
	Allison Randal <allison@lohutok.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Christoffer Dall <christoffer.dall@linaro.org>,
	Marc Zyngier <maz@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	clang-built-linux@googlegroups.com
Subject: Re: [RFC PATCH bpf-next 3/3] bpf, arm64: Optimize ADD,SUB,JMP BPF_K using arm64 add/sub immediates
Date: Thu, 7 May 2020 22:22:07 +0200	[thread overview]
Message-ID: <f93a921e-58d2-b7c4-0d3f-b76091c6b208@iogearbox.net> (raw)
In-Reply-To: <20200507010504.26352-4-luke.r.nels@gmail.com>

On 5/7/20 3:05 AM, Luke Nelson wrote:
> The current code for BPF_{ADD,SUB} BPF_K loads the BPF immediate to a
> temporary register before performing the addition/subtraction. Similarly,
> BPF_JMP BPF_K cases load the immediate to a temporary register before
> comparison.
> 
> This patch introduces optimizations that use arm64 immediate add, sub,
> cmn, or cmp instructions when the BPF immediate fits. If the immediate
> does not fit, it falls back to using a temporary register.
> 
> Example of generated code for BPF_ALU64_IMM(BPF_ADD, R0, 2):
> 
> without optimization:
> 
>    24: mov x10, #0x2
>    28: add x7, x7, x10
> 
> with optimization:
> 
>    24: add x7, x7, #0x2
> 
> The code could use A64_{ADD,SUB}_I directly and check if it returns
> AARCH64_BREAK_FAULT, similar to how logical immediates are handled.
> However, aarch64_insn_gen_add_sub_imm from insn.c prints error messages
> when the immediate does not fit, and it's simpler to check if the
> immediate fits ahead of time.
> 
> Co-developed-by: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>

Same here:

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

Thanks!

WARNING: multiple messages have this Message-ID (diff)
From: Daniel Borkmann <daniel@iogearbox.net>
To: Luke Nelson <lukenels@cs.washington.edu>, bpf@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
	Song Liu <songliubraving@fb.com>,
	Zi Shen Lim <zlim.lnx@gmail.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	John Fastabend <john.fastabend@gmail.com>,
	clang-built-linux@googlegroups.com,
	linux-arm-kernel@lists.infradead.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
	Xi Wang <xi.wang@gmail.com>, Luke Nelson <luke.r.nels@gmail.com>,
	Torsten Duwe <duwe@suse.de>, KP Singh <kpsingh@chromium.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Allison Randal <allison@lohutok.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Enrico Weigelt <info@metux.net>, Martin KaFai Lau <kafai@fb.com>,
	Christoffer Dall <christoffer.dall@linaro.org>
Subject: Re: [RFC PATCH bpf-next 3/3] bpf, arm64: Optimize ADD,SUB,JMP BPF_K using arm64 add/sub immediates
Date: Thu, 7 May 2020 22:22:07 +0200	[thread overview]
Message-ID: <f93a921e-58d2-b7c4-0d3f-b76091c6b208@iogearbox.net> (raw)
In-Reply-To: <20200507010504.26352-4-luke.r.nels@gmail.com>

On 5/7/20 3:05 AM, Luke Nelson wrote:
> The current code for BPF_{ADD,SUB} BPF_K loads the BPF immediate to a
> temporary register before performing the addition/subtraction. Similarly,
> BPF_JMP BPF_K cases load the immediate to a temporary register before
> comparison.
> 
> This patch introduces optimizations that use arm64 immediate add, sub,
> cmn, or cmp instructions when the BPF immediate fits. If the immediate
> does not fit, it falls back to using a temporary register.
> 
> Example of generated code for BPF_ALU64_IMM(BPF_ADD, R0, 2):
> 
> without optimization:
> 
>    24: mov x10, #0x2
>    28: add x7, x7, x10
> 
> with optimization:
> 
>    24: add x7, x7, #0x2
> 
> The code could use A64_{ADD,SUB}_I directly and check if it returns
> AARCH64_BREAK_FAULT, similar to how logical immediates are handled.
> However, aarch64_insn_gen_add_sub_imm from insn.c prints error messages
> when the immediate does not fit, and it's simpler to check if the
> immediate fits ahead of time.
> 
> Co-developed-by: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Xi Wang <xi.wang@gmail.com>
> Signed-off-by: Luke Nelson <luke.r.nels@gmail.com>

Same here:

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

Thanks!

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-05-07 20:22 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-07  1:05 [RFC PATCH bpf-next 0/3] arm64 BPF JIT Optimizations Luke Nelson
2020-05-07  1:05 ` Luke Nelson
2020-05-07  1:05 ` [RFC PATCH bpf-next 1/3] arm64: insn: Fix two bugs in encoding 32-bit logical immediates Luke Nelson
2020-05-07  1:05   ` Luke Nelson
2020-05-07  8:19   ` Marc Zyngier
2020-05-07  8:19     ` Marc Zyngier
2020-05-07  8:29   ` Will Deacon
2020-05-07  8:29     ` Will Deacon
2020-05-07  9:12     ` Marc Zyngier
2020-05-07  9:12       ` Marc Zyngier
2020-05-07 21:48       ` Luke Nelson
2020-05-07 21:48         ` Luke Nelson
2020-05-08 11:47         ` Will Deacon
2020-05-08 11:47           ` Will Deacon
2020-05-08 18:12           ` Luke Nelson
2020-05-08 18:12             ` Luke Nelson
2020-05-07  1:05 ` [RFC PATCH bpf-next 2/3] bpf, arm64: Optimize AND,OR,XOR,JSET BPF_K using arm64 " Luke Nelson
2020-05-07  1:05   ` [RFC PATCH bpf-next 2/3] bpf, arm64: Optimize AND, OR, XOR, JSET " Luke Nelson
2020-05-07 20:19   ` [RFC PATCH bpf-next 2/3] bpf, arm64: Optimize AND,OR,XOR,JSET " Daniel Borkmann
2020-05-07 20:19     ` Daniel Borkmann
2020-05-07  1:05 ` [RFC PATCH bpf-next 3/3] bpf, arm64: Optimize ADD,SUB,JMP BPF_K using arm64 add/sub immediates Luke Nelson
2020-05-07  1:05   ` [RFC PATCH bpf-next 3/3] bpf, arm64: Optimize ADD, SUB, JMP " Luke Nelson
2020-05-07 20:22   ` Daniel Borkmann [this message]
2020-05-07 20:22     ` [RFC PATCH bpf-next 3/3] bpf, arm64: Optimize ADD,SUB,JMP " Daniel Borkmann

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f93a921e-58d2-b7c4-0d3f-b76091c6b208@iogearbox.net \
    --to=daniel@iogearbox.net \
    --cc=allison@lohutok.net \
    --cc=andriin@fb.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=christoffer.dall@linaro.org \
    --cc=clang-built-linux@googlegroups.com \
    --cc=duwe@suse.de \
    --cc=info@metux.net \
    --cc=john.fastabend@gmail.com \
    --cc=kafai@fb.com \
    --cc=kpsingh@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luke.r.nels@gmail.com \
    --cc=lukenels@cs.washington.edu \
    --cc=mark.rutland@arm.com \
    --cc=maz@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=songliubraving@fb.com \
    --cc=tglx@linutronix.de \
    --cc=will@kernel.org \
    --cc=xi.wang@gmail.com \
    --cc=yhs@fb.com \
    --cc=zlim.lnx@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.