From owner-freebsd-arch@FreeBSD.ORG  Sun Oct 30 09:01:54 2011
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: arch@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 0A154106564A;
	Sun, 30 Oct 2011 09:01:54 +0000 (UTC) (envelope-from lev@FreeBSD.org)
Received: from onlyone.friendlyhosting.spb.ru (onlyone.friendlyhosting.spb.ru
	[IPv6:2a01:4f8:131:60a2::2])
	by mx1.freebsd.org (Postfix) with ESMTP id C18EF8FC08;
	Sun, 30 Oct 2011 09:01:53 +0000 (UTC)
Received: from lion.home.serebryakov.spb.ru (unknown
	[IPv6:2001:470:923f:1:504f:9791:43c0:21ab])
	(Authenticated sender: lev@serebryakov.spb.ru)
	by onlyone.friendlyhosting.spb.ru (Postfix) with ESMTPA id 805744AC1C; 
	Sun, 30 Oct 2011 13:01:52 +0400 (MSK)
Date: Sun, 30 Oct 2011 13:01:43 +0400
From: Lev Serebryakov <lev@FreeBSD.org>
Organization: FreeBSD Project
X-Priority: 3 (Normal)
Message-ID: <908954806.20111030130143@serebryakov.spb.ru>
To: Adrian Chadd <adrian@freebsd.org>
In-Reply-To: <CAJ-Vmo=D-b1SJ0WjJGGJ_WPK8FvE-fptDPRCGyMVhOm=FR8RYA@mail.gmail.com>
References: <201110281426.00013.jhb@freebsd.org> <4EAB550E.3060603@FreeBSD.org>
	<458756137.20111030024046@serebryakov.spb.ru>
	<CAJ-Vmo=D-b1SJ0WjJGGJ_WPK8FvE-fptDPRCGyMVhOm=FR8RYA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Cc: arch@freebsd.org
Subject: Re: [PATCH] fadvise(2) system call
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: lev@FreeBSD.org
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 30 Oct 2011 09:01:54 -0000

Hello, Adrian.
You wrote 30 =D0=BE=D0=BA=D1=82=D1=8F=D0=B1=D1=80=D1=8F 2011 =D0=B3., 4:05:=
19:

>>>> You can read the description of posix_fadvise() (which this implements=
) here:
>>> If you want a real-world consumer of posix_fadvise you can take a look
>>> at net-p2p/libtorrent-rasterbar15. The code is ifdef'ed out for FreeBSD
>>> because we don't have that yet, but it should be obvious how to
>>> re-enable it. There are a few clients that use that lib, qbittorrent is
>>> probably the most straightforward.
>> =C2=A0net-p2p/transmission-daemon could be used, too. It shows very poor
>> performance on UFS (90% in pread() call and 50% of wall time to
>> saturate 40Mbit/s channel from fast disk) compared to Linux, where
>> such interface exists.
> ... why? Squid/Lusca doesn't suffer that way.
   I don't know. But I could show your results of typical ktrace, where
 transmission-daemon spends 590 seconds of 600 (Wall time) in
 pread() syscall , and real read speed is only about 30Mbit/s (and
 this FS could be read at speed about 300MiB/s, 100 times faster,
 with linear read).

--=20
// Black Lion AKA Lev Serebryakov <lev@FreeBSD.org>