All of lore.kernel.org
 help / color / mirror / Atom feed
From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Yonghong Song <yhs@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Daniel Xu <dxu@dxuuu.xyz>,
	"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
	Song Liu <songliubraving@fb.com>,
	Andrii Nakryiko <andriin@fb.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	Alexei Starovoitov <ast@fb.com>,
	"alexander.shishkin@linux.intel.com" 
	<alexander.shishkin@linux.intel.com>,
	"jolsa@redhat.com" <jolsa@redhat.com>,
	"namhyung@kernel.org" <namhyung@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Kernel Team <Kernel-team@fb.com>,
	Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: Re: [PATCH v3 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl
Date: Wed, 21 Aug 2019 17:04:43 -0300	[thread overview]
Message-ID: <20190821200443.GH3929@kernel.org> (raw)
In-Reply-To: <5ecdcd72-255d-26d1-baf3-dc64498753c2@fb.com>

Em Wed, Aug 21, 2019 at 06:43:49PM +0000, Yonghong Song escreveu:
> On 8/21/19 11:31 AM, Peter Zijlstra wrote:
> > On Wed, Aug 21, 2019 at 04:54:47PM +0000, Yonghong Song wrote:
> >> A lot of bpf-based tracing programs uses maps to communicate and
> >> do not allocate ring buffer at all.
> > 
> > So extending PERF_RECORD_LOST doesn't work. But PERF_FORMAT_LOST might
> > still work fine; but you get to implement it for all software events.
> 
> Could you give more specifics about PERF_FORMAT_LOST? Googling 
> "PERF_FORMAT_LOST" only yields two emails which we are discussing here :-(

Perhaps he's talking about using read(perf_event_fd, ...) after having set it
up with perf_event_attr.read_format with the-to-be-implemented
PERF_FORMAT_LOST bit?

Look at perf_read() and perf_read_one() in kernel/events/core.c.
 
- Arnaldo

  reply	other threads:[~2019-08-21 20:04 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 22:31 [PATCH v3 bpf-next 0/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE Daniel Xu
2019-08-16 22:31 ` [PATCH v3 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl Daniel Xu
2019-08-19 18:22   ` kbuild test robot
2019-08-20  1:26   ` Alexei Starovoitov
2019-08-20  2:34     ` Daniel Xu
2019-08-20  2:52       ` Alexei Starovoitov
2019-08-20  2:04   ` kbuild test robot
2019-08-20 14:45   ` Peter Zijlstra
2019-08-20 17:58     ` Daniel Xu
2019-08-21 11:08       ` Peter Zijlstra
2019-08-21 16:54         ` Yonghong Song
2019-08-21 18:31           ` Peter Zijlstra
2019-08-21 18:43             ` Yonghong Song
2019-08-21 20:04               ` Arnaldo Carvalho de Melo [this message]
2019-08-22  7:47               ` Peter Zijlstra
2019-08-22  7:54                 ` Song Liu
2019-08-22  9:05                   ` Peter Zijlstra
2019-08-22 21:08                     ` Daniel Xu
2019-08-21 20:07           ` Arnaldo Carvalho de Melo
2019-08-21 22:10             ` Yonghong Song
2019-08-16 22:31 ` [PATCH v3 bpf-next 2/4] libbpf: Add helpers to extract perf fd from bpf_link Daniel Xu
2019-08-19 17:45   ` Andrii Nakryiko
2019-08-19 21:30     ` Daniel Xu
2019-08-16 22:31 ` [PATCH v3 bpf-next 3/4] tracing/probe: Sync perf_event.h to tools Daniel Xu
2019-08-16 22:31 ` [PATCH v3 bpf-next 4/4] tracing/probe: Add self test for PERF_EVENT_IOC_QUERY_PROBE Daniel Xu

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=20190821200443.GH3929@kernel.org \
    --to=arnaldo.melo@gmail.com \
    --cc=Kernel-team@fb.com \
    --cc=acme@redhat.com \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=andriin@fb.com \
    --cc=ast@fb.com \
    --cc=bpf@vger.kernel.org \
    --cc=dxu@dxuuu.xyz \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=namhyung@kernel.org \
    --cc=peterz@infradead.org \
    --cc=songliubraving@fb.com \
    --cc=yhs@fb.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.