From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E1C68C2BD09 for ; Mon, 15 Jul 2024 06:32:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sTFFI-0003F1-PY; Mon, 15 Jul 2024 02:31:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sTFFA-0002us-1N; Mon, 15 Jul 2024 02:31:30 -0400 Received: from mail-pg1-x52a.google.com ([2607:f8b0:4864:20::52a]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1sTFF8-0000IL-FZ; Mon, 15 Jul 2024 02:31:27 -0400 Received: by mail-pg1-x52a.google.com with SMTP id 41be03b00d2f7-6bce380eb9bso2342655a12.0; Sun, 14 Jul 2024 23:31:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1721025083; x=1721629883; darn=nongnu.org; h=in-reply-to:references:subject:cc:to:from:message-id:date :content-transfer-encoding:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=qVRZB5WwE5p0SELqCmw/YkHNB16dGeg/n+sVn1d43PI=; b=mjW8Rg6mIJ0uf6OPGzaTQm8Tqs/4MN+0hwH4DPOAUXoXYtnq+PnC94+ZgGD+wQY8pC ikLWSsppf2XJAq4v46DtyxlQiK1Mdz1JSHTLtz4j8GBLU/PXLkQslkKfgKgF3RnPGJo+ Dw9ZFiuc7Lj8KEWt8yh/BppbGyGZ0snRlulGgaNsU+EMHKmqtV3MlZnQG63V9wFeFJYr X4uSYp3sKYuNKExicb+2/v7DXmLweZoiSGCK/r4syDU14Rb5MUVGV3J19TsV2E8qV+AA QuWQMOIT9H0MVvCTpuRztnLgNJSrR3rI6of/N8/MUk5vLqhpuuPxJwCHXbaxvUeANxCm lOqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721025083; x=1721629883; h=in-reply-to:references:subject:cc:to:from:message-id:date :content-transfer-encoding:mime-version:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=qVRZB5WwE5p0SELqCmw/YkHNB16dGeg/n+sVn1d43PI=; b=hZS7SffQec9akLknYj28l9Vp9PTsAfFLceQ2Ficc10YkQnAYKSVdd1Tyey628xF9ut DXlzZ1FKF535lCy7ELmeWH8ca7G4Uq+WG6gwcbVLRMv/Hh+a8BivWFqd8O/WmKzWnbKi kx147VkoJHoA+pdsJpocW+wOwt9WKub1TL8X61Pmllnx7ZwUVQ4z4wTeasasN7BaXfl+ q+SrgWS3Fe4Xcdcl5lHAMzcysgEeZAWUh9rpid2pG20zuhTqtIqJTSUhA/6MQiNEbKpP Z55WUJHdUx9z2OxZFzG2TltCEidtcJpDxPwgWPDDTnAu0OBje7CwEJtnevfydQVUuQVT F5cQ== X-Forwarded-Encrypted: i=1; AJvYcCWbia6VVHaEdg4XHuL9i8de4MmUDPYLnE19lw1FceLVEQYWXKKccCfPlPnDXeUL+X6b+QAW2SW+Xc9ajzVH9urq1uSON5pxBc9QJtsM3Tl7aZuwH6zfM5gNPoU= X-Gm-Message-State: AOJu0Yysh/MSV98aGW1M4bUgcpuMrLrITQChsqvDefpFRk0sDECmPLLt b5eLO5anmrKTzQH4NlU4aHz22KxDxPCL5Kbk/8zBKYosKYBpEbTb X-Google-Smtp-Source: AGHT+IFCGHLGmIkF3tRyQX2jaALQ9tXnhmW1KIA5Oud+LnX9kXPQyLP4plo0Yq6RSo5a70CYDJ3RCw== X-Received: by 2002:a05:6a20:918c:b0:1bf:70c:b542 with SMTP id adf61e73a8af0-1c2984cab89mr23811229637.43.1721025083273; Sun, 14 Jul 2024 23:31:23 -0700 (PDT) Received: from localhost ([1.146.120.6]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2caedbfad6asm3543936a91.15.2024.07.14.23.31.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 14 Jul 2024 23:31:22 -0700 (PDT) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Mon, 15 Jul 2024 16:31:17 +1000 Message-Id: From: "Nicholas Piggin" To: =?utf-8?q?C=C3=A9dric_Le_Goater?= , Cc: =?utf-8?q?Fr=C3=A9d=C3=A9ric_Barrat?= , "Harsh Prateek Bora" , Subject: Re: [PATCH v2 10/19] ppc/pnv: Add a big-core mode that joins two regular cores X-Mailer: aerc 0.17.0 References: <20240712120247.477133-1-npiggin@gmail.com> <20240712120247.477133-11-npiggin@gmail.com> <4f0e918b-336f-4423-bc48-25607662eabc@kaod.org> In-Reply-To: <4f0e918b-336f-4423-bc48-25607662eabc@kaod.org> Received-SPF: pass client-ip=2607:f8b0:4864:20::52a; envelope-from=npiggin@gmail.com; helo=mail-pg1-x52a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Sat Jul 13, 2024 at 5:19 PM AEST, C=C3=A9dric Le Goater wrote: > On 7/12/24 14:02, Nicholas Piggin wrote: > > POWER9 and POWER10 machines come in two variants, big-core and > > small-core. Big-core machines are SMT8 from software's point of view, > > but the low level platform topology ("xscom registers and pervasive > > addressing"), these look more like a pair of small cores ganged > > together. > >=20 > > Presently the way this is modelled is to create one SMT8 PnvCore and ad= d > > special cases to xscom and pervasive for big-core mode that tries to > > split this into two small cores, but this is becoming too complicated t= o > > manage. > >=20 > > A better approach is to create 2 core structures and ganging them > > together to look like an SMT8 core in TCG. Then the xscom and pervasive > > models mostly do not need to differentiate big and small core modes. > >=20 > > This change adds initial mode bits and QEMU topology handling to > > split SMT8 cores into 2xSMT4 cores. > >=20 > > Signed-off-by: Nicholas Piggin > > > Looks good. See some proposal below, [snip] All make sense, thank you will do. Thnaks, Nick