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From: Yonghong Song <yonghong.song@linux.dev>
To: Andrii Nakryiko <andrii@kernel.org>,
	bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
	martin.lau@kernel.org
Cc: kernel-team@meta.com, John Fastabend <john.fastabend@gmail.com>
Subject: Re: [PATCH v3 bpf-next 2/2] bpf: inline bpf_get_branch_snapshot() helper
Date: Thu, 4 Apr 2024 10:44:06 -0700	[thread overview]
Message-ID: <ed69555b-2afb-4aac-8624-e51b47d537dc@linux.dev> (raw)
In-Reply-To: <20240404002640.1774210-3-andrii@kernel.org>


On 4/3/24 5:26 PM, Andrii Nakryiko wrote:
> Inline bpf_get_branch_snapshot() helper using architecture-agnostic
> inline BPF code which calls directly into underlying callback of
> perf_snapshot_branch_stack static call. This callback is set early
> during kernel initialization and is never updated or reset, so it's ok
> to fetch actual implementation using static_call_query() and call
> directly into it.
>
> This change eliminates a full function call and saves one LBR entry
> in PERF_SAMPLE_BRANCH_ANY LBR mode.
>
> Acked-by: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

Acked-by: Yonghong Song <yonghong.song@linux.dev>


  reply	other threads:[~2024-04-04 17:44 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-04  0:26 [PATCH v3 bpf-next 0/2] Inline bpf_get_branch_snapshot() BPF helper Andrii Nakryiko
2024-04-04  0:26 ` [PATCH v3 bpf-next 1/2] bpf: make bpf_get_branch_snapshot() architecture-agnostic Andrii Nakryiko
2024-04-04 17:25   ` Yonghong Song
2024-04-04  0:26 ` [PATCH v3 bpf-next 2/2] bpf: inline bpf_get_branch_snapshot() helper Andrii Nakryiko
2024-04-04 17:44   ` Yonghong Song [this message]
2024-04-04 18:14   ` Alexei Starovoitov
2024-04-04 18:28     ` Yonghong Song
2024-04-04 18:31       ` Alexei Starovoitov
2024-04-04 20:08         ` Andrii Nakryiko
2024-10-23  8:28   ` Shung-Hsi Yu
2024-10-23 16:04     ` Andrii Nakryiko
2024-04-04 20:20 ` [PATCH v3 bpf-next 0/2] Inline bpf_get_branch_snapshot() BPF helper patchwork-bot+netdevbpf

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