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 635DAEB64DA for ; Mon, 10 Jul 2023 12:41:08 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qIqCR-0007yX-3i; Mon, 10 Jul 2023 08:41:07 -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 1qIqCK-0007vy-Tl for qemu-devel@nongnu.org; Mon, 10 Jul 2023 08:41:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qIqCJ-0007CP-G1 for qemu-devel@nongnu.org; Mon, 10 Jul 2023 08:41:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688992858; 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: in-reply-to:in-reply-to:references:references; bh=QA9VrpLt5kpq5L3ikXfrFZrFGTdb++9t3ToNHTnsvsc=; b=MW4upWaZyHS5ztkwWHIxX1cz+hmtujMh3LU7GecUQiZihjbedw12OU2nvVk80kumLy4uST DsaoHR8VqA+Gyks+bel1KMkHtCRn5Zx9HRAqG9Cu9L0QLNMo6ye3aQLxPN22YXIuBzqTxk HMMtLdnH6xE2U02muHMKFGNZIDQCuKE= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-453-oWK4ZfrgOHK94FLrOgFJgQ-1; Mon, 10 Jul 2023 08:40:52 -0400 X-MC-Unique: oWK4ZfrgOHK94FLrOgFJgQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 5DB5B185A78B; Mon, 10 Jul 2023 12:40:52 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6E8C1C478DE; Mon, 10 Jul 2023 12:40:51 +0000 (UTC) Date: Mon, 10 Jul 2023 14:40:50 +0200 From: Kevin Wolf To: Klaus Jensen Cc: qemu-block@nongnu.org, richard.henderson@linaro.org, qemu-devel@nongnu.org, stefanha@redhat.com Subject: Re: [PULL 11/23] Revert "graph-lock: Disable locking for now" Message-ID: References: <20230628141526.293104-1-kwolf@redhat.com> <20230628141526.293104-12-kwolf@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Eng89UzZ8jWCZbEn" Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.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, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 --Eng89UzZ8jWCZbEn Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 10.07.2023 um 14:22 hat Klaus Jensen geschrieben: > On Jun 28 16:15, Kevin Wolf wrote: > > Now that bdrv_graph_wrlock() temporarily drops the AioContext lock that > > its caller holds, it can poll without causing deadlocks. We can now > > re-enable graph locking. > >=20 > > This reverts commit ad128dff0bf4b6f971d05eb4335a627883a19c1d. > >=20 >=20 > I'm seeing a pretty major performance regression on iothread-enabled > virtio-blk (and on some on-going iothread hw/nvme work) with this > applied. Something like ~300k iops prior to this vs ~200k after on my > set up. On master, virtio-blk is currently faster without an iothread > (~215k) than with (~200k). >=20 > I bisected the change in iops to this revert. Is CONFIG_DEBUG_GRAPH_LOCK enabled in your build? If so, this is expected to cost some performance. If not, we need to take a look at what else is causing the regression. Kevin --Eng89UzZ8jWCZbEn Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE3D3rFZqa+V09dFb+fwmycsiPL9YFAmSr/FIACgkQfwmycsiP L9Z8BhAAl48CiZB/w+bdTQ0ofhya09vqjuNPfuJEWT7K4JJ/FjAv8hVyjFyp2QTG Sr5KxZG2Y5CpFE0CgWqT5oGCt1rspPa4erMrKUcTCtRdj5qYIY0EFRutk/subbN7 JI9mXLAtkJWjb6xmyQ2S+5scTc6QPlql1foxi7Mkyn49NXAMdnQjULIwAluZ8sA2 0h+XGXNzTmZmwOs9z7FdnrdYK07uBinPHcteeotJl8ThJk9QhMYumKyV/USqZyts MyPNIl/wsA7uVAdFmzck6YrHXITGnFYq5z88lPcwzoi491OSmYRBRQv2paqlpYEV L5ILN8M+pABQWUyuhersQnLV0ZTP1plo3MTmAURvNX2ctdvU7y6syeB6ddes4rrO gnjlNl/rQ/rnb5uMItptlHmL+1mR3PciAu+KH/ZOfzYT3LEWNkh1LKA3lfmPh4q0 BCnjY+pclqWV8Ek+REJSaQLbs7HqnlCROMMr5TNbXCA/pZBO4b6+RFkVfWPlYy42 gbrFDVDMTCcdFtCR514cMq4nDUpd7gzkFKwSyVUDk87GEsf+Aqw/NJuzMpgRX87q b9vZiPtnSLVyCMpab3CspISW983ArYfuXy5JW9oMaGHpk5BqhLXfGFW5nYye3d4q 3rR2UQWGM71w7b9RxoDfx1cNbv1RpNrPCymNW3xixTCPcG6M4qo= =N6QT -----END PGP SIGNATURE----- --Eng89UzZ8jWCZbEn--