From: David Sterba <dsterba@suse.cz>
To: "Holger Hoffstätte" <holger@applied-asynchrony.com>
Cc: dsterba@suse.cz, Robbie Ko <robbieko@synology.com>,
linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v2] btrfs: speedup mount time with readahead chunk tree
Date: Wed, 8 Jul 2020 17:21:38 +0200 [thread overview]
Message-ID: <20200708152138.GB28832@twin.jikos.cz> (raw)
In-Reply-To: <de7bfbe5-7d83-2437-701c-700bbe5d3adc@applied-asynchrony.com>
On Wed, Jul 08, 2020 at 04:57:56PM +0200, Holger Hoffstätte wrote:
> On 2020-07-08 16:04, David Sterba wrote:
> > On Wed, Jul 08, 2020 at 10:19:22AM +0800, Robbie Ko wrote:
> >> David Sterba 於 2020/7/8 上午3:25 寫道:
> >> I don't know why we don't make the change to readahead, because the current
> >> readahead is limited to the logical address in 64k is very unreasonable,
> >> and there is a good chance that the logical address of the next leaf
> >> node will
> >> not appear in 64k, so the existing readahead is almost useless.
> >
> > I see and it seems that the assumption about layout and chances
> > succesfuly read blocks ahead is not valid. The logic of readahead could
> > be improved but that would need more performance evaluation.
>
> FWIW I gave this a try and see the following numbers, averaged over multiple
> mount/unmount cycles on spinning rust:
>
> without patch : ~2.7s
> with patch : ~4.5s
>
> ..ahem..
Hard to argue against numbers, thanks for posting that.
next prev parent reply other threads:[~2020-07-08 15:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 3:59 [PATCH v2] btrfs: speedup mount time with readahead chunk tree robbieko
2020-07-07 19:25 ` David Sterba
2020-07-08 2:19 ` Robbie Ko
2020-07-08 14:04 ` David Sterba
2020-07-08 14:57 ` Holger Hoffstätte
2020-07-08 15:21 ` David Sterba [this message]
2020-07-09 1:46 ` Robbie Ko
2020-07-09 7:17 ` Holger Hoffstätte
2020-07-08 21:11 ` David Sterba
2020-07-09 2:38 ` Robbie Ko
2020-07-09 9:13 ` David Sterba
2020-07-10 1:54 ` Robbie Ko
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