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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBA58C2D0DB for ; Thu, 30 Jan 2020 00:30:03 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id A361B206A2 for ; Thu, 30 Jan 2020 00:30:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="W6GX7tjR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A361B206A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:54142 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iwxic-0003HZ-Sy for qemu-devel@archiver.kernel.org; Wed, 29 Jan 2020 19:30:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54706) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iwxhz-0002mw-T5 for qemu-devel@nongnu.org; Wed, 29 Jan 2020 19:29:24 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iwxhz-0001sf-11 for qemu-devel@nongnu.org; Wed, 29 Jan 2020 19:29:23 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:53148 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iwxhy-0001r8-Sq for qemu-devel@nongnu.org; Wed, 29 Jan 2020 19:29:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580344162; 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=Fi2eDBSuxdfIYsIUjnM3VSpiM/8r9DeoW3vd4lBXuCM=; b=W6GX7tjR0NYe2nqD3/7otLt+ye90XIErnSGEhCWS8g8BdliUEycmHb6hcNNngJI9CG73N4 LPBcZ9K9V5T+oyy8b1GOYlPSkxdzylW7K8BpPm10jJF2xU88ZfZlvRzCXDwbkXiSqBi/de 8ZR4BDTz//YMaDK1f+3G3LZSh17wdaE= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-45-4rV7XawXMzi33VJ-N9GAkw-1; Wed, 29 Jan 2020 19:29:20 -0500 X-MC-Unique: 4rV7XawXMzi33VJ-N9GAkw-1 Received: by mail-wr1-f71.google.com with SMTP id k18so868896wrw.9 for ; Wed, 29 Jan 2020 16:29:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to; bh=WqI9SN3td3Cv+WjzpuVh/6ZvIzoOlE8LHcFFSgADh+I=; b=ivP9mCo7eMG9f7dN/zKDyoU+UlQkK/FN8y+On9ecf4VIDClLR4cnJq9mwXyOsO7p1W YxK2AMCu+AaQoUKgYLugClFtNqbCkBrrmlZwra52G5nxX/PGR7xuAatFn9LjXDYg083C 68/UUcdxkmKhO7gxplvC2GamOqnHLamPuFibURg1e/7R0k8eYwsHmaNf7W2aaUNSUfQO T3T/tePWHgKPuEUiW9URZsLzNDE4nCElGAjsa1DP10kF6VvduvFEMsHQMnuTfHN9nlk0 Emfdec0fE2fGi1piPOlQ+ztILLbec0fwZxCXKumws26jBFnAyWUntrsQVM2IviOmAGb1 3m1A== X-Gm-Message-State: APjAAAXYm0wYq3TGI2cHYzyXFDNZxUUK4hQlYlly5Xc4k/HchDxcpDbg jBZak8PyGG7SNOTCKJo3JJUNqAFdbK2hL1ExUYsXNcFlnpk/+qPwERsx9tPoC/Ae0RGjcVOBU+w odeMVw3lnJcx+wnk= X-Received: by 2002:a1c:7d8b:: with SMTP id y133mr1834065wmc.165.1580344159261; Wed, 29 Jan 2020 16:29:19 -0800 (PST) X-Google-Smtp-Source: APXvYqwievO+Xtx0RKuN7b/MhfFAdXCuaMPmrDIUvWlTMOTsWjPAwPNn4QwR/X5LpMgzGoce9uDz/A== X-Received: by 2002:a1c:7d8b:: with SMTP id y133mr1834026wmc.165.1580344158895; Wed, 29 Jan 2020 16:29:18 -0800 (PST) Received: from [10.1.251.141] ([80.188.125.198]) by smtp.gmail.com with ESMTPSA id q124sm12536514wme.2.2020.01.29.16.29.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Jan 2020 16:29:18 -0800 (PST) Subject: Re: [PATCH v2 2/4] virtio-scsi: default num_queues to -smp N To: Stefan Hajnoczi , Cornelia Huck References: <20200124100159.736209-1-stefanha@redhat.com> <20200124100159.736209-3-stefanha@redhat.com> <20200127141031.6e108839.cohuck@redhat.com> <20200129154438.GC157595@stefanha-x1.localdomain> From: Paolo Bonzini Message-ID: Date: Thu, 30 Jan 2020 01:29:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20200129154438.GC157595@stefanha-x1.localdomain> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="V9PgSakstXKJuYDCPCMItsOcM66U7cGuz" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , Eduardo Habkost , qemu-block@nongnu.org, "Michael S. Tsirkin" , qemu-devel@nongnu.org, Max Reitz , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --V9PgSakstXKJuYDCPCMItsOcM66U7cGuz Content-Type: multipart/mixed; boundary="reFCw68PV0ynBGseQj8l6NlmLjOkbFk9N" --reFCw68PV0ynBGseQj8l6NlmLjOkbFk9N Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 29/01/20 16:44, Stefan Hajnoczi wrote: > On Mon, Jan 27, 2020 at 02:10:31PM +0100, Cornelia Huck wrote: >> On Fri, 24 Jan 2020 10:01:57 +0000 >> Stefan Hajnoczi wrote: >>> @@ -47,10 +48,15 @@ static void vhost_scsi_pci_realize(VirtIOPCIProxy *= vpci_dev, Error **errp) >>> { >>> VHostSCSIPCI *dev =3D VHOST_SCSI_PCI(vpci_dev); >>> DeviceState *vdev =3D DEVICE(&dev->vdev); >>> - VirtIOSCSICommon *vs =3D VIRTIO_SCSI_COMMON(vdev); >>> + VirtIOSCSIConf *conf =3D &dev->vdev.parent_obj.parent_obj.conf; >>> + >>> + /* 1:1 vq to vcpu mapping is ideal because it avoids IPIs */ >>> + if (conf->num_queues =3D=3D VIRTIO_SCSI_AUTO_NUM_QUEUES) { >>> + conf->num_queues =3D current_machine->smp.cpus; >> This now maps the request vqs 1:1 to the vcpus. What about the fixed >> vqs? If they don't really matter, amend the comment to explain that? > The fixed vqs don't matter. They are typically not involved in the data > path, only the control path where performance doesn't matter. Should we put a limit on the number of vCPUs? For anything above ~128 the guest is probably not going to be disk or network bound. Paolo --reFCw68PV0ynBGseQj8l6NlmLjOkbFk9N-- --V9PgSakstXKJuYDCPCMItsOcM66U7cGuz Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAl4yI1wACgkQv/vSX3jH roNPfAf/ek8nDpe6SK47JUTwdBH6Ww0REcPD47plQEJnEkb3+KACWHOGFmBlms3+ QNTUvKR8R75ApOJ4HJy0Cvnjt/FhUkVe7isZaorY5J3AuBWOm25xIefVDDfpQnQi T8CPoN9ZwxD96ZOkPhROq4IVY9V8D0EbdWSay8LJKhysegJxRgwXQRO3NI0Bf6MO jDNWHK3wMH8c+Q6qvAu853K1K1UJnLnUisiZm3zwLHiFPoxAkiAMtP3HvhTejldF I0PP5HAOHtz2R4+/fCDPZGCeGU31FhaWuKlWBLfl6eIze3+Vwhfst54G9sP/Z4Eu g0RLfsg5tumnHEK+RLaC4mCrwE3qrw== =W0+E -----END PGP SIGNATURE----- --V9PgSakstXKJuYDCPCMItsOcM66U7cGuz--