From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by smtp.subspace.kernel.org (Postfix) with ESMTPS id 561591FC0
	for <patches@lists.linux.dev>; Thu, 21 Apr 2022 15:06:35 +0000 (UTC)
Received: from zn.tnic (p200300ea971b581b329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:971b:581b:329c:23ff:fea6:a903])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id BB1AE1EC047F;
	Thu, 21 Apr 2022 17:06:28 +0200 (CEST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim;
	t=1650553588;
	h=from:from:reply-to:subject:subject:date:date:message-id:message-id:
	 to:to:cc:cc:mime-version:mime-version:content-type:content-type:
	 content-transfer-encoding:in-reply-to:in-reply-to:  references:references;
	bh=1CUulx46ore+C/81/qYOIkQxt48mM0FBMnOdoOdynsM=;
	b=Y5WQgQ7AdYqN26pSEAyaqifnyv7y3UyqXatOJjJtM4KRl4sSRsf6nfMWgC+gQRdz9pyuSM
	bNRJEsP7STktDlc7gbAxOFEkHFnWJ5f0l9gVQJKF+bDPZj6JSQFc2sIduh/H3512ZICmmL
	hsP3VfP2sITOXEUMspyA+WVjZf3uErc=
Date: Thu, 21 Apr 2022 17:06:24 +0200
From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Hemment <markhemm@googlemail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	the arch/x86 maintainers <x86@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>, patrice.chotard@foss.st.com,
	Mikulas Patocka <mpatocka@redhat.com>,
	Lukas Czerner <lczerner@redhat.com>, Christoph Hellwig <hch@lst.de>,
	"Darrick J. Wong" <djwong@kernel.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	Hugh Dickins <hughd@google.com>, patches@lists.linux.dev,
	Linux-MM <linux-mm@kvack.org>, mm-commits@vger.kernel.org
Subject: Re: [patch 02/14] tmpfs: fix regressions from wider use of ZERO_PAGE
Message-ID: <YmFy8DEqvX4FlnuB@zn.tnic>
References: <Ylr8rR+LHQ1uGL47@zn.tnic>
 <CAHk-=wgt=H-LXpXpsqS+nYQU4p+jW4izGs5RVS6k9uj0g_J2VQ@mail.gmail.com>
 <Ylsx5PwyUPOainHa@zn.tnic>
 <YlxtTNFP58TcUHZQ@zn.tnic>
 <CAHk-=wiB8GXu84rChFvUZoZDfp6LnTuLruc0xoxj=mStmK-b1Q@mail.gmail.com>
 <Yl06PWVgeZplboXV@zn.tnic>
 <CAHk-=wh3ZFnUs+k0w3yTth8Kiy8xK45jo2VaT7x_-VFFMBVZiw@mail.gmail.com>
 <Yl5+DCfQmG5C3BHf@zn.tnic>
 <CAHk-=wi1iQXd3SSoyWZebdxdK3gFCVGq9q=4pwq3rON3BYZJkA@mail.gmail.com>
 <Yl7146AZDgfLviVv@zn.tnic>
Precedence: bulk
X-Mailing-List: patches@lists.linux.dev
List-Id: <patches.lists.linux.dev>
List-Subscribe: <mailto:patches+subscribe@lists.linux.dev>
List-Unsubscribe: <mailto:patches+unsubscribe@lists.linux.dev>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <Yl7146AZDgfLviVv@zn.tnic>

Some numbers with the microbenchmark:

$ for i in $(seq 1 100); do dd if=/dev/zero of=/dev/null bs=16K count=10000 2>&1 | grep GB; done > /tmp/w.log
$ awk 'BEGIN { sum = 0 } { sum +=$10 } END { print sum/100 }' /tmp/w.log

on AMD zen3

original:	20.11 Gb/s
rep_good:	34.662 Gb/s
erms:		36.378 Gb/s
fsrm:		36.398 Gb/s

I'll run some real benchmarks later but these numbers kinda speak for
themselves so it would be unlikely that it would show different perf
with a real, process-intensive benchmark...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette