From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dieter =?iso-8859-1?q?N=FCtzel?= <Dieter.Nuetzel@hamburg.de>
Subject: Re: Horrible ftruncate performance
Date: Wed, 16 Jul 2003 12:47:53 +0200
Message-ID: <200307161247.53880.Dieter.Nuetzel@hamburg.de>
References: <Pine.LNX.4.30.0307151407100.6563-100000@divine.city.tvnet.hu> <200307152155.09716.Dieter.Nuetzel@hamburg.de> <20030716103539.GB4955@namesys.com>
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To: Oleg Drokin <green@namesys.com>
Cc: Chris Mason <mason@suse.com>, Szakacsits Szabolcs <szaka@sienet.hu>, Carl-Daniel Hailfinger <c-d.hailfinger.kernel.2003@gmx.net>, reiserfs-list@namesys.com

Am Mittwoch, 16. Juli 2003 12:35 schrieb Oleg Drokin:
> Hello!
>
> On Tue, Jul 15, 2003 at 09:55:09PM +0200, Dieter N?tzel wrote:
> > Somewhat.
> > Mouse movement is OK, now. But...
> >
> > 1+0 Records aus
> > 0.000u 3.090s 0:16.81 18.3%     0+0k 0+0io 153pf+0w
> > 0.000u 0.050s 0:00.27 18.5%     0+0k 0+0io 122pf+0w
> > INSTALL/SOURCE> time dd if=/dev/zero of=sparse1 bs=1 seek=200G count=1 ;
> > time sync
> > 1+0 Records ein
> > 1+0 Records aus
> > 0.000u 3.010s 0:15.27 19.7%     0+0k 0+0io 153pf+0w
> > 0.000u 0.020s 0:01.01 1.9%      0+0k 0+0io 122pf+0w
>
> So you create a file in 15 seconds

Right.

> and remove it in 15 seconds.

No. "Normaly" ~5 seconds.

INSTALL/SOURCE> time rm sparse2 ; time sync
0.000u 4.930s 0:04.88 101.0%    0+0k 0+0io 130pf+0w
0.000u 0.010s 0:00.02 50.0%     0+0k 0+0io 122pf+0w

> Kind of nothing changed except mouse now moves,

Yes.

> am I reading this wrong?

No. ;-)

> > INSTALL/SOURCE> time rm sparse ; time sync
> > 0.000u 14.990s 1:31.15 16.4%    0+0k 0+0io 130pf+0w
> > 0.000u 0.030s 0:00.22 13.6%     0+0k 0+0io 122pf+0w
>
> So the stuff fell out of cache and we need to read it again.

Shouldn't this take only 15 seconds, then?
Worst case was ~5 minutes.

> hence the increased time. Hm, probably this case can be optimized
> if there is only one item in the leaf and this item should be removed.
> Need to take closer look to balancing code.

Now, out of office.

Greetings,
	Dieter