From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f176.google.com (mail-yw1-f176.google.com [209.85.128.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 14C4A1F1302 for ; Fri, 26 Sep 2025 16:45:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758905147; cv=none; b=h5cMeiqFBd1cLxGNP6wesP2xJy9IvvapEpKDjw2GG5lKTWYsEzdV+gIR3piHclHXf69p00GBDmnJodZxoqOlxIwyw+KxZvyoKc1XCACqP0ICms0ZEsO+YlkprEnTePdAECLl/c9Q2km/FHLAyJL/H8NhsD0MjJAuxIbeqPoNUEc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758905147; c=relaxed/simple; bh=Vs6TAGLNP0P+xmbqBciKFWYHtBQhY1DI1fGlxkQza8E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=GooYe855CBA6w2IVsVw7ETePOkVKmzgz5KVU2sM0xwxa4LtqnriLtbqO3ACqt3Tp0EZAqQs1xrHgbdh1e8bS3gyjis6XBAbonTyAtk6vwFZgAbAgIuuE4szRDNkmst+Bg0ij8wZbTljdwB9Z288t80frCX+d1JTVMJkIvrWM2uc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=kdSYuNVf; arc=none smtp.client-ip=209.85.128.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kdSYuNVf" Received: by mail-yw1-f176.google.com with SMTP id 00721157ae682-71d603b674aso24392557b3.1 for ; Fri, 26 Sep 2025 09:45:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1758905145; x=1759509945; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=rWe6l9DFEZIe2QF5kWTxkiV4TR1qHm+R41H6tLR7BcY=; b=kdSYuNVflSeyGs5exn2hCuFEhA/ar3DNYHXHMbOPamsIprarYpTD/N0qyrz6fQUWXB I9ZKQr9o1NVVic3cnUPTf8fsYMrT4zaasu84yQ75dBmTJp4zWBdYZg8vN5NGlnCvkWkw iJ6GSvEa78eLw0aYSYLaoUR1RR52IAzb6ZWL1iPpzk/o6JtizVsUQAwqlkhbHSbO/u3h 0FyCWNKL6pj0gBIkcUT5qs01ViPgvzPODmdhiDMYBfhHb+E3ElbGpdBbO7nv2APHkHua uRKRN7xMSoaIhZc8R1NwGa6era3VDyR7gXTrOasVfyzGefV0iyLKXe56YVW0I9ANOTr3 nzgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1758905145; x=1759509945; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=rWe6l9DFEZIe2QF5kWTxkiV4TR1qHm+R41H6tLR7BcY=; b=phE95XAmDVErGt4/6CpGRpsMOfQhgkDkSlRHWEIx74yRTkpfEZrpWYcw8c54KtLGyD hyYiWXGsrhQObdKUGezoHNwpUCmLiSH4FlIFQ4VfUJzgscUDzw7N6lN9XLVrzDqhjHZD htyGoU+HAJnH+vAE/E5KESmRZ4PxZE99vNRB3afkOiyMuFlJfzqi/WUBFZTBt79cniiJ 6L5Njf7dj0254BrkHG0S0m9sg/2vnN/XzHe1ACIKO5VvZlZrmCua96hYn2XcqMT/ZRPi v7nNwkYhc7a8R09KW70jvppTousFv5OzRVeZwRirJ/eBgNeiY1NL21lACs9wgz11b4+x 5nmQ== X-Forwarded-Encrypted: i=1; AJvYcCXBhqrO6B9oijWubkAU2HbzpuhSJ0xon5FTkJRhbwyLv9RNOucLC3ihcJmPWlYKZz/NSCmmyNwqUgp5FnU=@vger.kernel.org X-Gm-Message-State: AOJu0YwBuLN5mACYN9rc4/DsOmwbXpqV1B6RDmFBwVHcrN9H/Ah0mM1K LWqQ+c3qHcY8weYwSSgtoEOVlgn1JSXqbf+9ovXpNOw8KcEZ0eKt11k8 X-Gm-Gg: ASbGncvs8Oauw5PhH//48Hrt73lQiMSvEcwrn1LRuVinaxO1R9jdZqMMnMZeKSzMnOk p48lMfPiiyuujAjNLtxQBJf/Qbsi2ATTVtP5o1dNequB8prCLSYQ6toD8G/beDhOac0jsRAoXuL rVsDiyuvAxnb0eHT7ttXm1SuX2qnqQdGxHU8OQQL6EsrpOn8cdrnjwrPW6iFk2FfJ1Hne/kiUf7 LzXruP/JV/QImdZQg8jOcZVd/WkGrBRbk3AnQ4ImTt+sIQ0NXZHVswxHtJMnZ63eMh4DB7IuasL km9G60gtuGohRn3Cp9RHyAk+n6JKzIeTHqrAbjZUbKKdE7R19G9lUB8i98iyy3QTFxsgFQSqEob 34AlB9naP13ddFJK6zXce7jKuoJZTvbbGGnU1GWyMjiYNgI5Nn1rRrVF5Ow== X-Google-Smtp-Source: AGHT+IFpF5cWlNLrT5bHlj24v+44FGgh9yJp1dc+sghREQUf8FAhAKLzfo2Kz30PeNG78RhjMp14pA== X-Received: by 2002:a05:690c:6c84:b0:763:e43b:3ab6 with SMTP id 00721157ae682-763eae4da07mr94212387b3.0.1758905144931; Fri, 26 Sep 2025 09:45:44 -0700 (PDT) Received: from devvm11784.nha0.facebook.com ([2a03:2880:25ff:70::]) by smtp.gmail.com with ESMTPSA id 00721157ae682-765be47f630sm12074467b3.29.2025.09.26.09.45.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Sep 2025 09:45:44 -0700 (PDT) Date: Fri, 26 Sep 2025 09:45:42 -0700 From: Bobby Eshleman To: Simon Horman Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kuniyuki Iwashima , Willem de Bruijn , Neal Cardwell , David Ahern , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Stanislav Fomichev , Mina Almasry , Bobby Eshleman Subject: Re: [PATCH net-next v3 0/2] net: devmem: improve cpu cost of RX token management Message-ID: References: <20250926-scratch-bobbyeshleman-devmem-tcp-token-upstream-v3-0-084b46bda88f@meta.com> 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: On Fri, Sep 26, 2025 at 04:55:01PM +0100, Simon Horman wrote: > On Fri, Sep 26, 2025 at 08:02:52AM -0700, Bobby Eshleman wrote: > > This series improves the CPU cost of RX token management by replacing > > the xarray allocator with an niov array and a uref field in niov. > > > > Improvement is ~5% per RX user thread. > > > > Two other approaches were tested, but with no improvement. Namely, 1) > > using a hashmap for tokens and 2) keeping an xarray of atomic counters > > but using RCU so that the hotpath could be mostly lockless. Neither of > > these approaches proved better than the simple array in terms of CPU. > > > > Running with a NCCL workload is still TODO, but I will follow up on this > > thread with those results when done. > > > > Signed-off-by: Bobby Eshleman > > Hi Bobby, > > Unfortunately this patchset doesn't apply cleanly to net-next. > So you'll need to rebase and repost at some point. > > -- > pw-bot: changes-requested Got it, just resent and added this check to my automation, thanks! Best, Bobby