From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id A161248B6C; Fri, 21 Nov 2025 18:12:05 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 94803402EE; Fri, 21 Nov 2025 18:12:05 +0100 (CET) Received: from mail-pg1-f169.google.com (mail-pg1-f169.google.com [209.85.215.169]) by mails.dpdk.org (Postfix) with ESMTP id 391B840267 for ; Fri, 21 Nov 2025 18:12:03 +0100 (CET) Received: by mail-pg1-f169.google.com with SMTP id 41be03b00d2f7-bc8ceb76c04so1509906a12.1 for ; Fri, 21 Nov 2025 09:12:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20230601.gappssmtp.com; s=20230601; t=1763745122; x=1764349922; darn=dpdk.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=6NydMEeRVBSTrU7RWQJWsBxYyJGcrnVfi0Ih3fQnSkc=; b=P+McosGhfi3h2mgWBI0E24alxovmEDYJE7y8XqIRHrM1pUjQxahFB/UM23biv8EmPU xMkiYJgRtfVdqRx+VVJ2xHixL+2DHGh/CvSiVXJn/WsqVbFWlG1Mg59WXVlJa8+5MgOo zSnkLi6nNRkCsrxAYerRYYvX+QzTuF0nIW/gSoXlSrs4OkThC7gfX9iJffm8f3phbbxs GKQlqedQXxe1S3xxOHO6PenZdzJ3o0TokkSHKa7vewMk3ML8SYHYUMjiGtv2gHdnQkis 1/lEKgaQZhW7tu+X/sL/EVHQDdMz+e9//A253p9EQOHKFOXBqYdrhqn6PgbGtN2IXyd1 3Whw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763745122; x=1764349922; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=6NydMEeRVBSTrU7RWQJWsBxYyJGcrnVfi0Ih3fQnSkc=; b=kO5CQeuGV68Q3l81Asbp6HcuFRSKs8htOZf4SoNVcU2sgYXxVwu6qti/U9A6LnTOSR IWa8c1+m6Di+pwDD/v4Yx3/uZR2ud6wRuEBX8CR/Bjx790KwaMnjmdCkxT5C8h/7STvl oCXR5TlF+2l7mFjPlLSN3G6l7uDo1/mhUbmW2LFQSoKgolbF/HIjMeSNGuyk+t86yCSV uRXjVm13ojBFGS8B+zHPeBophYYqR4/yJb5m/3bLeaPuiatQVkA2gV4htTC75gpaDgg9 j6HrrLNaPGC//SgXbPaTDqQ3gZlR2k3r540Ne68A1OuYK4ZJnsfq8qTF7xf70blCxuCa WN7A== X-Forwarded-Encrypted: i=1; AJvYcCXs/vQZWQ/pswGDsIZ1IrEiqhKMP3isoskd5cvBKf6a+I1gFTo7xpwlZd2jFduySm5eUnU=@dpdk.org X-Gm-Message-State: AOJu0YyOz0UAEJY/kIH7nmEJChoHdh7c4SaN7EwgLqsN1x6uvxxfr3q0 CBhoMOKj8Gba12krVjAaVN4dj1G7iDk2sQ39XLOCjCLxbZeKEbFYzjkaT0yYsC+mv18= X-Gm-Gg: ASbGncu4HLUodTxkU+ddsENLiB6uhYhFv1Liv/OvzSMlGNC4FWP4j5CeD/6aCMuZtO8 tsntUXx2Dljkyp3to1bXqTFShJ8k+Tai3N81LV1zAwic7kmf9fZlLwql0Ff0/phr83OhK3QY6vQ G63VjRJ0sDviGsOfkpf3ZrORlPEqjR8S3kv5BpGMyxobNEFTg0kiDOwkBnc+W/nvO/B2kjlu0Z0 ap1zRSt4Mn6bNo/2nyrgr/A0O+7pMJUDNjEHkekqUCHVKSSGsIwfhnd9qnUAZzJvKQ7BDyiuI1g mfC9mAv3QnLX2P8z+KT5KCCdtr1I6UGZTCL6WrcKVRs6IC5GBb+mEHinMff1P5Abf3ipYYyvpH5 7NkaSlDG5BlOMArccffqD7EV/7FalyVQVwPDSmTqcYChLztdDcwymqvwAQkEqrzNb7VXtVYKjPx lQrtmwQ9JQJuhtgCCjH6ak6jb856NJ2jbSUN9l8XLKoytLbLiwwktZ X-Google-Smtp-Source: AGHT+IGWWeqtPjTdcQEzl9bM4GtE3pFN5rWz/DbK8hdZyO9qxhMAQhx+h+EYQZxZzCqG2d7O8WFWdw== X-Received: by 2002:a05:7301:fc0e:b0:2a4:7599:29fb with SMTP id 5a478bee46e88-2a719c2944dmr889103eec.36.1763745122177; Fri, 21 Nov 2025 09:12:02 -0800 (PST) Received: from phoenix.local (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2a6fc3d0bb6sm31280612eec.2.2025.11.21.09.12.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Nov 2025 09:12:01 -0800 (PST) Date: Fri, 21 Nov 2025 09:11:59 -0800 From: Stephen Hemminger To: Bruce Richardson Cc: Morten =?UTF-8?B?QnLDuHJ1cA==?= , , Konstantin Ananyev , "Vipin Varghese" Subject: Re: [PATCH v2] eal/x86: optimize memcpy of small sizes Message-ID: <20251121091159.4783d97b@phoenix.local> In-Reply-To: References: <20251120114554.950287-1-mb@smartsharesystems.com> <20251121103535.1273457-1-mb@smartsharesystems.com> <20251121085730.51f0466a@phoenix.local> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On Fri, 21 Nov 2025 17:02:17 +0000 Bruce Richardson wrote: > > As I have said before would rather that DPDK move away from having its > > own specialized memcpy. How is this compared to stock inline gcc? > > The main motivation is that the glibc/gcc team does more testing across > > multiple architectures and has a community with more expertise on CPU > > special cases. > > I would tend to agree. Even if we get rte_memcpy a few cycles faster, I > suspect many apps wouldn't notice the difference. However, I understand > that the virtio/vhost libraries gain from using rte_memcpy over standard > memcpy - or at least used to. Perhaps we can consider deprecating > rte_memcpy and just putting a vhost-specific memcpy in that library? It would be good to figure out why vhost is better with rte_memcpy, maybe there is some alignment assumption that is in one and not the other?