From nobody Sat Apr 11 23:03:17 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1773069096; cv=none; d=zohomail.com; s=zohoarc; b=RksscnzcgFQJ9dSl+C4TpZySXhclGQ+6FuNy35wQLSoa2q8BEz2IIZSoP5JTe8+fL00xlSDpF7FS1HAVlyjEKNHcrHdtD/+sV8D32iwRxfnGjKlxrQDDcH9IoarldQXEIdl6d5dHWNJrWkNL03b6X2LTyjOC788wsZcvjnllKSE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1773069096; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=/nvY+FQXOEd7mADtviTKG5X4XDtAjCV+MockVMSjqaI=; b=YEWGchxh+W3/ZtytWCiqRbpwKupDG+yMYsuOkJi/XSa4/RSVGQoGh4uiI3bpxDgOw3aoakI6Dk9HsbFY9jgS0DkV90qfPoj464uhB/iFqOy2fXnTWT4mtWHyDhJUUXEnl1gu7e50nKeZtczPjDk4cxq6s1LQsEAKHFNOvRrcTN4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1773069096894795.294012677535; Mon, 9 Mar 2026 08:11:36 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vzcGP-0003Ue-H2; Mon, 09 Mar 2026 11:11:21 -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 1vzcFP-0001gw-9l for qemu-devel@nongnu.org; Mon, 09 Mar 2026 11:10:30 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vzcFG-0000Hz-SR for qemu-devel@nongnu.org; Mon, 09 Mar 2026 11:10:13 -0400 Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-530-fnYNy0oAPU66XbE3NDkCKA-1; Mon, 09 Mar 2026 11:10:06 -0400 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-4853ac455b2so12474815e9.1 for ; Mon, 09 Mar 2026 08:10:06 -0700 (PDT) Received: from localhost (p200300cfd737d0cf29d515fbd6051d53.dip0.t-ipconnect.de. [2003:cf:d737:d0cf:29d5:15fb:d605:1d53]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-485245dbe50sm91408945e9.17.2026.03.09.08.10.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Mar 2026 08:10:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773069007; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/nvY+FQXOEd7mADtviTKG5X4XDtAjCV+MockVMSjqaI=; b=D8YG34+jjwta7P4Ndo8Z3aO2mD3LzqxWnRJNqiUrt5/D0jYOLKGSX+oIk1x0m92qIG3ncN b65xWF8V/S1QurYRRn4JspaTnAppxw0rBl5KBPJPKH5p9GW3TXP64dV/zYfbw9GaAfLnx9 hc3gdiAIpP3iC9VTGM++n5nFsy1DwCQ= X-MC-Unique: fnYNy0oAPU66XbE3NDkCKA-1 X-Mimecast-MFC-AGG-ID: fnYNy0oAPU66XbE3NDkCKA_1773069005 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1773069005; x=1773673805; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=/nvY+FQXOEd7mADtviTKG5X4XDtAjCV+MockVMSjqaI=; b=dXRWrzARBBNyg/qVYYducm74ox3QsCIempB3Hr18Hgl5UjE/KMOFCcLa43tPm/FPFx sSA65VHOfGi/fhn7OEaurERLNoHQ765CayNqeKLNAPNLGkJMDBLgjh2sUYXhrqj1Dqov nTsLDG3a38bcGnC0jOmBx2EegL5B56lw+KAaRx2/kNaq0OpjgD+WXmITYTyq+FUNuAYx c0dOu8/fFI2m8fclA1Cn5Cm2RlPU1utivYfs/JFsNLAVqIAJ8et2CVl84nGZdzZSNKGL h8B0vP9ohz+uoZdCvg494A/DH3StsDs5V7CPXmp8isUB/A6ZL6mm4kBZFAP6UMKHCwbB rvig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1773069005; x=1773673805; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=/nvY+FQXOEd7mADtviTKG5X4XDtAjCV+MockVMSjqaI=; b=VDGWkXceKnYrYyxemzPjefvNkYX0Z3dcdvlPr/yqrdU9lO/7/yUTxClkZ1PbaSQsQs sGYeAKmh5AeMmlOxEIhEvR+WwoXIY8roIqk0kBC6D9B3ZHXAO0H+Jjy1IKvwbC+TOLC4 UJH4GTTsATBcWZw+ZBDYfob9rr/cX56ES3ufDcEgWBtD3PPJnwpaZ9Y5innHkNpLOoRw /F76EE+Hg3KP3hMBWxYhl6wPZw+JVJcP8ZwC5MrLhhf+niiTgEKhZx4Hj9XL7A7fmNPY rcd4p/VQ9xs93PLXzg3532vF5a07/wBe1CEAt1ScezioDb5RxYHUYKP3Z1qmZUFaPpi9 JfSg== X-Gm-Message-State: AOJu0Yya59Bxbd5DInKi7hEsV7zAwKPJXmgs7HqilcaaGH9diBGFL6kK mEPjbPuvBPB0snbbJsSU/25jNVLLjME6zYWOlGFJWGStbBM1+eEFlG/vCQzZU1xK8gZTeFaGi00 w+s1fFO3Ey+RGg11EzZMBSENd43drTBYOUFq75nGfgEfanabHtkT2yWjC X-Gm-Gg: ATEYQzyEP07ZTZ6Jld3ARQHQeXJzkXFDdsAsGGrQINoTJ6hXT8xtBQG+3MRtfzNLcOO TONPO3irBOQZWBZIzftf4Y5/av3Xcac6hEQ7XyT0odiY8vKZD8xXLl3DtcHYdX1OpguM21WrxAP MvUYg9SM2z8w1QZqt6Q5mQRiuFyS9pdvM7bN0vODgsTrUG+MdkU8UHMilIcV98kxePT2VCP+4ef bEV/Wh5dNdMSGtCDP0YOUwrXIDl8c2jmLCkIfrfK+E3e8RUMq3j1PmRH6CDXAtxgr9CvVI/2EjA +I4/DV+sZra9S5JuYLFjm9C/AClbqPk9qowgZa5qKZlZh58iieIThlk94lrvdu8eB2QdaUsShSw z1fhMmqucVjqOkFGFIvzGshJAEYq1Rex5buY7WbFU0oIzSjRBBKt6eW/orka2ZjMOxFEiPOs2O3 BvJu/3 X-Received: by 2002:a05:600c:4445:b0:483:6a8d:b2f9 with SMTP id 5b1f17b1804b1-4852690febamr208987695e9.5.1773069004998; Mon, 09 Mar 2026 08:10:04 -0700 (PDT) X-Received: by 2002:a05:600c:4445:b0:483:6a8d:b2f9 with SMTP id 5b1f17b1804b1-4852690febamr208986955e9.5.1773069004559; Mon, 09 Mar 2026 08:10:04 -0700 (PDT) From: Hanna Czenczek To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Czenczek , Kevin Wolf , Brian Song Subject: [PATCH v5 24/25] qapi/block-export: Document FUSE's multi-threading Date: Mon, 9 Mar 2026 16:08:55 +0100 Message-ID: <20260309150856.26800-25-hreitz@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260309150856.26800-1-hreitz@redhat.com> References: <20260309150856.26800-1-hreitz@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1773069098164154100 Content-Type: text/plain; charset="utf-8" Document for users that FUSE's multi-threading implementation distributes requests in a round-robin manner, regardless of where they originate from. As noted by Stefan, this will probably change with a FUSE-over-io_uring implementation (which is supposed to have CPU affinity), but documenting that is left for once that is done. Suggested-by: Stefan Hajnoczi Acked-by: Markus Armbruster Signed-off-by: Hanna Czenczek --- qapi/block-export.json | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/qapi/block-export.json b/qapi/block-export.json index 160cd2e3ca..dd724acf1c 100644 --- a/qapi/block-export.json +++ b/qapi/block-export.json @@ -164,6 +164,11 @@ # Options for exporting a block graph node on some (file) mountpoint # as a raw image. # +# Multi-threading note: The FUSE export supports multi-threading. +# Currently, requests are distributed across these threads in a +# round-robin fashion, i.e. independently of the CPU core from which a +# request originates. +# # @mountpoint: Path on which to export the block device via FUSE. # This must point to an existing regular file. # --=20 2.53.0