linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: David Miller <davem@davemloft.net>
To: acme@kernel.org
Cc: jolsa@redhat.com, linux-kernel@vger.kernel.org,
	namhyung@kernel.org, jolsa@kernel.org
Subject: Re: [PATCH RFC] hist lookups
Date: Wed, 07 Nov 2018 22:04:24 -0800 (PST)	[thread overview]
Message-ID: <20181107.220424.2221817007547297022.davem@davemloft.net> (raw)
In-Reply-To: <20181107202815.GH18346@kernel.org>

From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: Wed, 7 Nov 2018 17:28:15 -0300

> So perhaps we should tell the kernel that is ok to lose SAMPLEs but not
> the other events, and make userspace ask for PERF_RECORD_!SAMPLE in all
> ring buffers? Duplication wouldn't be that much of a problem?

I think we should strive to keep the policy in userspace.

The kernel simply provides the events that happen, and the user's
job is to take the events in sort of a "high priority interrupt"
context and push the slow path processing to a separate thread of
execution where drop policy can be implemented.

Jiri's work provides a framework for exactly that.

So what we can have is:

	cpu1  cpu2  cpu3  cpu4  cpu5  cpu6 ... cpuN
	|     |     |     |     |     |        |
	----------------------------------------
	                  |
			  |
			  | single event ring buffer
			  |
			  |
		ultra-fast perf event dequeue
	     queues in-order to event processing
		          |
		  event processing slow path
	        prioritization and drop policy
		     histogram insert
		        etc.

  reply	other threads:[~2018-11-08  6:04 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31  5:03 [PATCH RFC] hist lookups David Miller
2018-10-31 12:43 ` Arnaldo Carvalho de Melo
2018-10-31 15:39   ` Jiri Olsa
2018-10-31 16:08     ` David Miller
2018-11-03  6:30       ` David Miller
2018-11-04 20:18         ` Jiri Olsa
2018-11-05  0:50           ` David Miller
2018-11-05 20:34             ` Jiri Olsa
2018-11-05 22:52               ` David Miller
2018-11-06  3:45               ` David Miller
2018-11-06  4:03                 ` David Miller
2018-11-06  4:53                   ` David Miller
2018-11-06 11:54                     ` Jiri Olsa
2018-11-19  5:26                       ` Namhyung Kim
2018-11-19  9:12                         ` Jiri Olsa
2018-11-20  1:13                           ` Namhyung Kim
2018-11-06 20:42                     ` Jiri Olsa
2018-11-07  6:13                       ` David Miller
2018-11-07  8:32                         ` Jiri Olsa
2018-11-07 19:43                           ` Jiri Olsa
2018-11-07 20:01                             ` David Miller
2018-11-07 20:28                               ` Arnaldo Carvalho de Melo
2018-11-08  6:04                                 ` David Miller [this message]
2018-11-08  7:13                               ` Jiri Olsa
2018-11-09  1:07                                 ` David Miller
2018-11-11 19:41                                   ` Jiri Olsa
2018-11-11 19:41                                     ` Jiri Olsa
2018-11-11 22:32                                     ` David Miller
2018-11-11 22:43                                       ` Jiri Olsa
2018-11-11 22:58                                         ` David Miller
2018-11-11 23:08                                     ` David Miller
2018-11-11 23:26                                       ` Jiri Olsa
2018-11-11 23:32                                         ` David Miller
2018-11-13 10:40                                           ` Jiri Olsa
2018-11-19  4:52                                             ` David Miller
2018-11-19  6:28                                               ` Namhyung Kim
2018-11-19  6:33                                                 ` David Miller
2018-11-19  7:16                                                   ` Namhyung Kim
2018-11-19  9:14                                               ` Jiri Olsa
2018-11-06 11:51                 ` Jiri Olsa

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=20181107.220424.2221817007547297022.davem@davemloft.net \
    --to=davem@davemloft.net \
    --cc=acme@kernel.org \
    --cc=jolsa@kernel.org \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=namhyung@kernel.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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).