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From: Florent Revest <revest@chromium.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Xu Kuohai <xukuohai@huawei.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Xu Kuohai <xukuohai@huaweicloud.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Ingo Molnar <mingo@redhat.com>, Oleg Nesterov <oleg@redhat.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>, Zi Shen Lim <zlim.lnx@gmail.com>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Guo Ren <guoren@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH bpf-next v2 0/4] Add ftrace direct call for arm64
Date: Wed, 5 Oct 2022 17:10:33 +0200	[thread overview]
Message-ID: <CABRcYmJGY6fp0CtUBYN8BjEDN=r42BPLSBcrxqu491bTRmfm7g@mail.gmail.com> (raw)
In-Reply-To: <20221005110707.55bd9354@gandalf.local.home>

On Wed, Oct 5, 2022 at 5:07 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Wed, 5 Oct 2022 22:54:15 +0800
> Xu Kuohai <xukuohai@huawei.com> wrote:
>
> > 1.3 attach bpf prog with with direct call, bpftrace -e 'kfunc:vfs_write {}'
> >
> > # dd if=/dev/zero of=/dev/null count=1000000
> > 1000000+0 records in
> > 1000000+0 records out
> > 512000000 bytes (512 MB, 488 MiB) copied, 1.72973 s, 296 MB/s
> >
> >
> > 1.4 attach bpf prog with with indirect call, bpftrace -e 'kfunc:vfs_write {}'
> >
> > # dd if=/dev/zero of=/dev/null count=1000000
> > 1000000+0 records in
> > 1000000+0 records out
> > 512000000 bytes (512 MB, 488 MiB) copied, 1.99179 s, 257 MB/s

Thanks for the measurements Xu!

> Can you show the implementation of the indirect call you used?

Xu used my development branch here
https://github.com/FlorentRevest/linux/commits/fprobe-min-args

As it stands, the performance impact of the fprobe based
implementation would be too high for us. I wonder how much Mark's idea
here https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/ftrace/per-callsite-ops
would help but it doesn't work right now.

  reply	other threads:[~2022-10-05 15:10 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-13 16:27 [PATCH bpf-next v2 0/4] Add ftrace direct call for arm64 Xu Kuohai
2022-09-13 16:27 ` [PATCH bpf-next v2 1/4] ftrace: Allow users to disable ftrace direct call Xu Kuohai
2022-09-13 16:27 ` [PATCH bpf-next v2 2/4] arm64: ftrace: Support long jump for " Xu Kuohai
2022-09-13 16:27 ` [PATCH bpf-next v2 3/4] arm64: ftrace: Add ftrace direct call support Xu Kuohai
2022-09-13 16:27 ` [PATCH bpf-next v2 4/4] ftrace: Fix dead loop caused by direct call in ftrace selftest Xu Kuohai
2022-09-22 18:01 ` [PATCH bpf-next v2 0/4] Add ftrace direct call for arm64 Daniel Borkmann
2022-09-26 14:40   ` Catalin Marinas
2022-09-26 17:43     ` Mark Rutland
2022-09-27  4:49       ` Xu Kuohai
2022-09-28 16:42         ` Mark Rutland
2022-09-30  4:07           ` Xu Kuohai
2022-10-04 16:06             ` Florent Revest
2022-10-05 14:54               ` Xu Kuohai
2022-10-05 15:07                 ` Steven Rostedt
2022-10-05 15:10                   ` Florent Revest [this message]
2022-10-05 15:30                     ` Steven Rostedt
2022-10-05 22:12                       ` Jiri Olsa
2022-10-06 16:35                         ` Florent Revest
2022-10-06 10:09                       ` Xu Kuohai
2022-10-06 16:19                       ` Florent Revest
2022-10-06 16:29                         ` Steven Rostedt
2022-10-07 10:13                           ` Xu Kuohai
2022-10-17 17:55                           ` Florent Revest
2022-10-17 18:49                             ` Steven Rostedt
2022-10-17 19:10                               ` Florent Revest
2022-10-21 11:31                             ` Masami Hiramatsu
2022-10-21 16:49                               ` Florent Revest
2022-10-24 13:00                                 ` Masami Hiramatsu
2022-11-10  4:58                                 ` wuqiang
2022-10-06 10:09           ` Xu Kuohai

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