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[209.132.180.67]) by mx.google.com with ESMTP id w3-v6si10956719plp.526.2018.03.06.06.50.32; Tue, 06 Mar 2018 06:50:46 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@amazon.com header.s=amazon201209 header.b=X3S1lgDT; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=amazon.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753878AbeCFOoA (ORCPT + 99 others); Tue, 6 Mar 2018 09:44:00 -0500 Received: from smtp-fw-9102.amazon.com ([207.171.184.29]:37734 "EHLO smtp-fw-9102.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753790AbeCFOjm (ORCPT ); Tue, 6 Mar 2018 09:39:42 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1520347182; x=1551883182; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=YIB+YzaJUfL9G0OpACgeCDbi7VvcPkDfLJuoOyLiz/U=; b=X3S1lgDTwEkTt5KkHgWjm6/njpHHimqQ7Bsa72TJsgq2rQauwvhGf2en HcpeLmVWTQVkd3RbfXiW3WjYZTEwGDh4f5Bhp7vpCreii81fXVFJBZdIb EVoe+ePOrnljuFQWZFT7pEa6yQNZxoZsxCbH4vVvlwGA8p03uFPQBwV+e 4=; X-IronPort-AV: E=Sophos;i="5.47,431,1515456000"; d="scan'208";a="598137756" Received: from sea3-co-svc-lb6-vlan3.sea.amazon.com (HELO email-inbound-relay-2c-397e131e.us-west-2.amazon.com) ([10.47.22.38]) by smtp-border-fw-out-9102.sea19.amazon.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 06 Mar 2018 14:39:40 +0000 Received: from EX13MTAUWC001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-2c-397e131e.us-west-2.amazon.com (8.14.7/8.14.7) with ESMTP id w26Eddl0069554 (version=TLSv1/SSLv3 cipher=AES256-SHA bits=256 verify=FAIL); Tue, 6 Mar 2018 14:39:40 GMT Received: from EX13D16UWC002.ant.amazon.com (10.43.162.161) by EX13MTAUWC001.ant.amazon.com (10.43.162.135) with Microsoft SMTP Server (TLS) id 15.0.1236.3; Tue, 6 Mar 2018 14:39:39 +0000 Received: from EX13MTAUWC001.ant.amazon.com (10.43.162.135) by EX13D16UWC002.ant.amazon.com (10.43.162.161) with Microsoft SMTP Server (TLS) id 15.0.1236.3; Tue, 6 Mar 2018 14:39:39 +0000 Received: from localhost (10.85.222.111) by mail-relay.amazon.com (10.43.162.232) with Microsoft SMTP Server id 15.0.1236.3 via Frontend Transport; Tue, 6 Mar 2018 14:39:39 +0000 Date: Tue, 6 Mar 2018 06:39:39 -0800 From: Eduardo Valentin To: Wanpeng Li CC: , , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Eduardo Habkost Subject: Re: [PATCH v4 0/3] KVM: Introduce dedicated vCPUs hint KVM_HINTS_DEDICATED Message-ID: <20180306143939.GA23766@u40b0340c692b58f6553c.ant.amazon.com> References: <1518483942-14741-1-git-send-email-wanpengli@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1518483942-14741-1-git-send-email-wanpengli@tencent.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Folks, On Tue, Feb 13, 2018 at 09:05:39AM +0800, Wanpeng Li wrote: > This patchset introduces dedicated vCPUs(vCPU pinning, and there is no > vCPU over-commitment) hint KVM_HINTS_DEDICATED, it has two users now: > > 1) Waiman Long mentioned that: > > Generally speaking, unfair lock performs well for VMs with a small > number of vCPUs. Native qspinlock may perform better than pvqspinlock > if there is vCPU pinning and there is no vCPU over-commitment. > > 2) vCPUs are very unlikely to get preempted when they are the only task > running on a CPU. PV TLB flush is slower that the native flush in that > case. > > v3 -> v4: > * update feature bit document > v2 -> v3: > * a separate table for CPUID[0x40000001].EDX bits > * a new kvm_hint_has_feature macro > v1 -> v2: > * update to KVM_HINTS_DEDICATED Great to see this has finally moved forward! Thanks for picking it up Wanpeng. I would just request to next time at least reference the original thread and copy the original authors of the patch/idea. Thanks a lot. -- All the best, Eduardo Valentin