Date: Wed, 15 Apr 2015 20:37:12 +0200
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
        One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
        Jiri Kosina <jkosina@suse.cz>, Al Viro <viro@zeniv.linux.org.uk>,
        Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@amacapital.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Tom Gundersen <teg@jklm.no>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Daniel Mack <daniel@zonque.org>,
        David Herrmann <dh.herrmann@gmail.com>,
        Djalal Harouni <tixxdz@opendz.org>
Subject: Re: [GIT PULL] kdbus for 4.1-rc1
Message-ID: <20150415183712.GA30280@kroah.com>
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On Wed, Apr 15, 2015 at 11:28:58AM -0700, Linus Torvalds wrote:
> On Wed, Apr 15, 2015 at 11:18 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > I've seen this claimed, but I have never seen any actual numbers. What
> > speeds up? By how much? is it actually measurable?
> 
> And just to clarify: by "what speeds up, and by how much", I do _not_
> mean "sending a dbus message speeds up by 10x and avoids context
> switches". I've seen _those_ numbers. But does it actually matter?
> 
> It was more of a "there are thousands of dbus messages during boot,
> but can you actually measure the speedup?" question. That's the kind
> of numbers I've not seen.

Someone from BMW did the testing on one of their car systems a while ago
and posted some numbers, it was a factor of 10 faster.  I'll try to dig
it up, but it was burried in a powerpoint presentation, so it might be
hard to find, give me a day.

thanks,

greg k-h
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