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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-46a3eb175eesm80725521cf.55.2024.12.27.07.40.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Dec 2024 07:40:38 -0800 (PST) From: Gregory Price X-Google-Original-From: Gregory Price Date: Fri, 27 Dec 2024 10:40:36 -0500 To: "Huang, Ying" Cc: Gregory Price , linux-mm@kvack.org, linux-kernel@vger.kernel.org, nehagholkar@meta.com, abhishekd@meta.com, kernel-team@meta.com, david@redhat.com, nphamcs@gmail.com, akpm@linux-foundation.org, hannes@cmpxchg.org, kbusch@meta.com Subject: Re: [RFC v2 PATCH 0/5] Promotion of Unmapped Page Cache Folios. Message-ID: References: <20241210213744.2968-1-gourry@gourry.net> <87o715r4vn.fsf@DESKTOP-5N7EMDA> <87wmfsi47b.fsf@DESKTOP-5N7EMDA> <87v7v5g99x.fsf@DESKTOP-5N7EMDA> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87v7v5g99x.fsf@DESKTOP-5N7EMDA> On Fri, Dec 27, 2024 at 10:16:42AM +0800, Huang, Ying wrote: > Gregory Price writes: > > > On Sun, Dec 22, 2024 at 03:09:44PM +0800, Huang, Ying wrote: > >> Gregory Price writes: > >> > That's 3-6% performance in this contrived case. > >> > >> This is small too. > >> > > > > Small is relative. 3-6% performance increase across millions of servers > > across a year is a non trivial speedup for such a common operation. > > If we cannot only get 3-6% performance increase in a micro-benchmark, > how much can we get from a real life workloads? > > Anyway, we need to prove the usefulness of the change via data. 3-6% > isn't some strong data. > > Can we measure the largest improvement? For example, run the benchmark > with all file pages in DRAM and CXL.mem via numa binding, and compare. > I can probably come up with something, will rework some stuff. ~Gregory