BPF Archive on lore.kernel.org
 help / color / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Kris Van Hees <kris.van.hees@oracle.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	dtrace-devel@oss.oracle.com, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, mhiramat@kernel.org, acme@kernel.org,
	ast@kernel.org, daniel@iogearbox.net
Subject: Re: [RFC PATCH 00/11] bpf, trace, dtrace: DTrace BPF program type implementation and sample use
Date: Fri, 24 May 2019 09:27:26 +0200
Message-ID: <20190524072726.GD2589@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190522182215.GO2422@oracle.com>

On Wed, May 22, 2019 at 02:22:15PM -0400, Kris Van Hees wrote:

> > Let me further NAK it for adding all sorts of garbage to the code --
> > we're not going to do gaps and stay_in_page nonsense.
> 
> Could you give some guidance in terms of an alternative?  The ring buffer code
> provides both non-contiguous page allocation support and a vmalloc-based
> allocation, and the vmalloc version certainly would avoid the entire gap and
> page boundary stuff.  But since the allocator is chosen at build time based on
> the arch capabilities, there is no way to select a specific memory allocator.
> I'd be happy to use an alternative approach that allows direct writing into
> the ring buffer.

So why can't you do what the regular perf does? Use an output iterator
that knows about the page breaks? See perf_output_put() for example.

Anyway, I agree with Alexei and DaveM, get it working without/minimal
kernel changes first, and then we can talk about possible optimizations.

  parent reply index

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20 23:47 Kris Van Hees
2019-05-21 17:56 ` Alexei Starovoitov
2019-05-21 18:41   ` Kris Van Hees
2019-05-21 20:55     ` Alexei Starovoitov
2019-05-21 21:36       ` Steven Rostedt
2019-05-21 21:43         ` Alexei Starovoitov
2019-05-21 21:48           ` Steven Rostedt
2019-05-22  5:23             ` Kris Van Hees
2019-05-22 20:53               ` Alexei Starovoitov
2019-05-23  5:46                 ` Kris Van Hees
2019-05-23 21:13                   ` Alexei Starovoitov
2019-05-23 23:02                     ` Steven Rostedt
2019-05-24  0:31                       ` Alexei Starovoitov
2019-05-24  1:57                         ` Steven Rostedt
2019-05-24  2:08                           ` Alexei Starovoitov
2019-05-24  2:40                             ` Steven Rostedt
2019-05-24  5:26                             ` Kris Van Hees
2019-05-24  5:10                       ` Kris Van Hees
2019-05-24  4:05                     ` Kris Van Hees
2019-05-24 13:28                       ` Steven Rostedt
2019-05-21 21:36       ` Kris Van Hees
2019-05-21 23:26         ` Alexei Starovoitov
2019-05-22  4:12           ` Kris Van Hees
2019-05-22 20:16             ` Alexei Starovoitov
2019-05-23  5:16               ` Kris Van Hees
2019-05-23 20:28                 ` Alexei Starovoitov
2019-05-30 16:15                   ` Kris Van Hees
2019-05-31 15:25                     ` Chris Mason
2019-06-06 20:58                       ` Kris Van Hees
2019-06-18  1:25                   ` Kris Van Hees
2019-06-18  1:32                     ` Alexei Starovoitov
2019-06-18  1:54                       ` Kris Van Hees
2019-06-18  3:01                         ` Alexei Starovoitov
2019-06-18  3:19                           ` Kris Van Hees
2019-05-22 14:25   ` Peter Zijlstra
2019-05-22 18:22     ` Kris Van Hees
2019-05-22 19:55       ` Alexei Starovoitov
2019-05-22 20:20         ` David Miller
2019-05-23  5:19         ` Kris Van Hees
2019-05-24  7:27       ` Peter Zijlstra [this message]
2019-05-21 20:39 ` [RFC PATCH 01/11] bpf: context casting for tail call Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 02/11] bpf: add BPF_PROG_TYPE_DTRACE Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 03/11] bpf: export proto for bpf_perf_event_output helper Kris Van Hees
     [not found] ` <facilities>
2019-05-21 20:39   ` [RFC PATCH 04/11] trace: initial implementation of DTrace based on kernel Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 05/11] trace: update Kconfig and Makefile to include DTrace Kris Van Hees
     [not found] ` <features>
2019-05-21 20:39   ` [RFC PATCH 06/11] dtrace: tiny userspace tool to exercise DTrace support Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 07/11] bpf: implement writable buffers in contexts Kris Van Hees
2019-05-21 20:39 ` [RFC PATCH 08/11] perf: add perf_output_begin_forward_in_page Kris Van Hees
     [not found] ` <the>
     [not found]   ` <context>
2019-05-21 20:39     ` [RFC PATCH 09/11] bpf: mark helpers explicitly whether they may change Kris Van Hees
     [not found] ` <helpers>
2019-05-21 20:39   ` [RFC PATCH 10/11] bpf: add bpf_buffer_reserve and bpf_buffer_commit Kris Van Hees
2019-05-21 20:40 ` [RFC PATCH 11/11] dtrace: make use of writable buffers in BPF Kris Van Hees
2019-05-21 20:48 ` [RFC PATCH 00/11] bpf, trace, dtrace: DTrace BPF program type implementation and sample use Kris Van Hees
2019-05-21 20:54   ` Steven Rostedt
2019-05-21 20:56   ` Alexei Starovoitov

Reply instructions:

You may reply publically 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=20190524072726.GD2589@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=acme@kernel.org \
    --cc=alexei.starovoitov@gmail.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=dtrace-devel@oss.oracle.com \
    --cc=kris.van.hees@oracle.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mhiramat@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    /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

BPF Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/bpf/0 bpf/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 bpf bpf/ https://lore.kernel.org/bpf \
		bpf@vger.kernel.org bpf@archiver.kernel.org
	public-inbox-index bpf


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.bpf


AGPL code for this site: git clone https://public-inbox.org/ public-inbox