Netdev List
 help / color / mirror / Atom feed
From: David Howells <dhowells@redhat.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: dhowells@redhat.com, David Ahern <dsahern@gmail.com>,
	netdev@vger.kernel.org, linux-afs@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next] udp: Add tracepoints to monitor skbs going in and out of a UDP socket
Date: Fri, 05 Oct 2018 07:46:50 +0100	[thread overview]
Message-ID: <9724.1538722010@warthog.procyon.org.uk> (raw)
In-Reply-To: <20181005020316.7cqlcfkedhamwhtt@ast-mbp.dhcp.thefacebook.com>

Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:

> - kprobes at the top of the function don't use traps and they've been
> optimized over the years to have very low overhead

To quote kprobes.txt:

	How Does a Kprobe Work?
	-----------------------

	When a kprobe is registered, Kprobes makes a copy of the probed
	instruction and replaces the first byte(s) of the probed instruction
	with a breakpoint instruction (e.g., int3 on i386 and x86_64).

Perhaps the docs need updating.

However, for my purposes, tracepoints are easier.

Anyway, as I said, I don't feel that strongly about the patch.  It was useful
for me, and I thought it might be useful for other people.

David

      reply	other threads:[~2018-10-05  6:46 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-04  8:30 [PATCH net-next] udp: Add tracepoints to monitor skbs going in and out of a UDP socket David Howells
2018-10-04 16:36 ` David Ahern
2018-10-04 16:54   ` David Howells
2018-10-04 17:19     ` Alexei Starovoitov
2018-10-04 23:24       ` David Howells
2018-10-05  2:03         ` Alexei Starovoitov
2018-10-05  6:46           ` David Howells [this message]

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=9724.1538722010@warthog.procyon.org.uk \
    --to=dhowells@redhat.com \
    --cc=alexei.starovoitov@gmail.com \
    --cc=dsahern@gmail.com \
    --cc=linux-afs@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.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