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Wed, 1 Apr 2026 14:14:10 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id LyX7IzIozWlRdQAAD6G6ig (envelope-from ); Wed, 01 Apr 2026 14:14:10 +0000 Date: Wed, 1 Apr 2026 15:14:08 +0100 From: Pedro Falcato To: "David Hildenbrand (Arm)" Cc: Andrew Morton , Luke Yang , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Dev Jain , jhladky@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Nico Pache Subject: Re: [PATCH v2 0/2] mm/mprotect: micro-optimization work Message-ID: References: <20260324154342.156640-1-pfalcato@suse.de> <20260330130635.1d8bf3f1f9dfcafc0317f5e7@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Action: no action X-Rspamd-Queue-Id: 2F22E80014 X-Stat-Signature: zwybehrjc93x5611t6rgarqxtxst8mch X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1775052852-520570 X-HE-Meta: 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 Naj6ygfT wpr9URk0o9NAx63P/s2OV06csc/ZjLufSOiVS5EYr3QPicHa13voLURvojociPCNDdkCxUKZMNBpDAYEwnyCVrapEd4wiq4loLNG2vnaZveQDOz2Gr3q0JxdIEnWL5Kjwi09Ry1qmlNHfX4wf2d59+YIHm9rhWcqEZSzcoZxDAGbdraUflXHaUXHeB0d1Iirru5nAdVG6r0VQxPna6Q+7D83VXud4LSuZvzpNO9DYkSRhv+XzkG34bvoVpHL3LTBgBcJssAWj0qvHJDBCa1Mk8VImHhC3sI1iLylWCGsXTZjvWi1wlaTPAsF8dHAbjzX7Q7Swihs8NBv8/kL7eh2xZ2crJL3k0SZvaEh/ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Apr 01, 2026 at 10:25:40AM +0200, David Hildenbrand (Arm) wrote: > On 3/30/26 22:06, Andrew Morton wrote: > > On Mon, 30 Mar 2026 15:55:51 -0400 Luke Yang wrote: > > > >> Thanks for working on this. I just wanted to share that we've created a > >> test kernel with your patches and tested on the following CPUs: > >> > >> --- aarch64 --- > >> Ampere Altra > >> Ampere Altra Max > >> > >> --- x86_64 --- > >> AMD EPYC 7713 > >> AMD EPYC 7351 > >> AMD EPYC 7542 > >> AMD EPYC 7573X > >> AMD EPYC 7702 > >> AMD EPYC 9754 > >> Intel Xeon Gold 6126 > >> Into Xeon Gold 6330 > >> Intel Xeon Gold 6530 > >> Intel Xeon Platinum 8351N > >> Intel Core i7-6820HQ > >> > >> --- ppc64le --- > >> IBM Power 10 > >> > >> On average, we see improvements ranging from a minimum of 5% to a > >> maximum of 55%, with most improvements showing around a 25% speed up in > >> the libmicro/mprot_tw4m micro benchmark. > > > > Thanks, that's nice. I've added some of the above into the changelog > > and I took the liberty of adding your Tested-by: to both patches. > > > > fyi, regarding [2/2]: it's unclear to me whether the discussion with > > David will result in any alterations. If there's something I need to > > it always helps to lmk ;) > > I think we want to get a better understanding of which exact __always_inline > is really helpful in patch #2, and where to apply the nr_ptes==1 forced > optimization. > > I updated my microbenchmark I use for fork+unmap etc to measure > mprotect as well > > https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/pte-mapped-folio-benchmarks.c?ref_type=heads > > Running some simple tests with order-0 on 1 GiB of memory: > > > Upstream Linus: > > ./pte-mapped-folio-benchmarks 0 write-protect 5 > 0.005779 > ... > ./pte-mapped-folio-benchmarks 0 write-unprotect 5 > 0.009113 > ... > > > With Pedro's patch #2: > $ ./pte-mapped-folio-benchmarks 0 write-protect 5 > 0.003941 > ... > $ ./pte-mapped-folio-benchmarks 0 write-unprotect 5 > 0.006163 > ... > > > With the patch below: > > $ ./pte-mapped-folio-benchmarks 0 write-protect 5 > 0.003364 > > $ ./pte-mapped-folio-benchmarks 0 write-unprotect 5 > 0.005729 Hmm. Thanks for the testing. Interesting. I'll give it a shot. I'll have results and/or a possible v3 by tomorrow, if need be. Apologies for the slight delay here! :) -- Pedro