From: David Sterba <dsterba@suse.cz>
To: Zaslonko Mikhail <zaslonko@linux.ibm.com>
Cc: Qu Wenruo <quwenruo.btrfs@gmx.com>, Qu Wenruo <wqu@suse.com>,
linux-btrfs@vger.kernel.org, linux-s390@vger.kernel.org,
Vasily Gorbik <gor@linux.ibm.com>
Subject: Re: [PATCH] btrfs: zlib: do not do unnecessary page copying for compression
Date: Tue, 28 May 2024 23:43:50 +0200 [thread overview]
Message-ID: <20240528214350.GI8631@twin.jikos.cz> (raw)
In-Reply-To: <2db8bc9a-5ff0-40ec-92ba-29c90b6976c7@linux.ibm.com>
On Tue, May 28, 2024 at 12:44:19PM +0200, Zaslonko Mikhail wrote:
> > But I'm still wondering if we do not go 4 pages as buffer, how much
> > performance penalty would there be?
> >
> > One of the objective is to prepare for the incoming sector perfect
> > subpage compression support, thus I'm re-checking the existing
> > compression code, preparing to change them to be subpage compatible.
> >
> > If we can simplify the behavior without too large performance penalty,
> > can we consider just using one single page as buffer?
>
> Based on my earlier estimates, bigger buffer provided up to 60% performance for inflate and up to 30% for
> deflate on s390 with dfltcc support.
> I don't think giving it away for simplification would be a good idea.
60% and 30% sound like significant gain, I agree this takes precedence
over code simplification. Eventually the s390 optimized case can be
moved to a separate function if the conditions are satisfied so it's not
mixed with the page-by-page code.
next prev parent reply other threads:[~2024-05-28 21:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-27 9:24 [PATCH] btrfs: zlib: do not do unnecessary page copying for compression Qu Wenruo
2024-05-27 16:25 ` Zaslonko Mikhail
2024-05-27 22:09 ` Qu Wenruo
2024-05-28 10:44 ` Zaslonko Mikhail
2024-05-28 21:43 ` David Sterba [this message]
2024-05-28 22:02 ` Qu Wenruo
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