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From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: davem@davemloft.net, alexei.starovoitov@gmail.com, tgraf@suug.ch,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 1/3] perf, events: add non-linear data support for raw records
Date: Wed, 13 Jul 2016 09:52:09 +0200	[thread overview]
Message-ID: <20160713075209.GQ30154@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <f6ffffc1011706426682be92f80fc6aa6a8cc196.1468362046.git.daniel@iogearbox.net>

On Wed, Jul 13, 2016 at 12:36:17AM +0200, Daniel Borkmann wrote:
> This patch adds support for non-linear data on raw records. It means
> that for such data, the newly introduced __output_custom() helper will
> be used instead of __output_copy(). __output_custom() will invoke
> whatever custom callback is passed in via struct perf_raw_record_frag
> to extract the data into the ring buffer slot.
> 
> To keep changes in perf_prepare_sample() and in perf_output_sample()
> minimal, size/size_head split was added to perf_raw_record that call
> sites fill out, so that two extra tests in fast-path can be avoided.
> 
> The few users of raw records are adapted to initialize their size_head
> and frag data; no change in behavior for them. Later patch will extend
> BPF side with a first user and callback for this facility, future users
> could be things like XDP BPF programs (that work on different context
> though and would thus have a different callback), etc.

Why? What problem are we solving?

  reply	other threads:[~2016-07-13  7:52 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12 22:36 [PATCH net-next 0/3] BPF event output helper improvements Daniel Borkmann
2016-07-12 22:36 ` [PATCH net-next 1/3] perf, events: add non-linear data support for raw records Daniel Borkmann
2016-07-13  7:52   ` Peter Zijlstra [this message]
2016-07-13  9:24     ` Daniel Borkmann
2016-07-13 12:10       ` Peter Zijlstra
2016-07-13 13:16         ` Daniel Borkmann
2016-07-13 13:42   ` Peter Zijlstra
2016-07-13 14:08     ` Daniel Borkmann
2016-07-13 16:40       ` Peter Zijlstra
2016-07-13 16:53         ` Daniel Borkmann
2016-07-12 22:36 ` [PATCH net-next 2/3] bpf, perf: split bpf_perf_event_output Daniel Borkmann
2016-07-12 22:36 ` [PATCH net-next 3/3] bpf: avoid stack copy and use skb ctx for event output Daniel Borkmann
2016-07-12 23:25   ` kbuild test robot
2016-07-12 23:45     ` Daniel Borkmann
2016-07-13  0:01       ` Fengguang Wu

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