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received-spf: None (protection.outlook.com: microsoft.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: 04hBRLa6MIz2TwWcYU4tuA/fhjw6hb/eFilg3jwNmAT7AfORkRMK1OalQW9hK5cU6YEwHuBtfU3tdVlPcminvujZRPgVEOHq2IlwYU3wC45TfZLO5j81N/4FFB5wkG1QgQ18cycpxqfBxB5YG2ULY4Ldgm5DJUZrNeC7ehJy6fr5o4Bk+vaItWnCIWVeQnHmfP/rNsa9iFupzR+0o5ahmVPAhuhZ3z5/g9LbgnuEwx0a7j/j1jlBWhmZpjCP2hsJd/cqLpU14kcsQmhXu6ZqdzjwnkjNhbMwTjxxxBmkcoZ6scDY5x3KI2FtXDdBMn+iTAPEeOGJjv7nkHGa18HsbYz/SA1MX3otRCEcDuJCHnf26PuhfmuNEhRAy5fc36U3g/+3FVvm84thcjd40PYZsk1mxaJbax5USp7pOb9Q2Es= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 5b1ad6db-d1e6-452e-98ce-08d6c2016d4a X-MS-Exchange-CrossTenant-originalarrivaltime: 16 Apr 2019 00:21:10.1623 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR21MB0779 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>Subject: Re: [PATCH] x86/hyper-v: implement EOI assist >>> >>>Vitaly Kuznetsov writes: >>> >>>> Hyper-V TLFS suggests an optimization to avoid imminent VMExit on EOI: >>>> "The OS performs an EOI by atomically writing zero to the EOI Assist >>>> field of the virtual VP assist page and checking whether the "No EOI >>>required" >>>> field was previously zero. If it was, the OS must write to the >>>> HV_X64_APIC_EOI MSR thereby triggering an intercept into the >>>hypervisor." >>>> >>>> Implement the optimization in Linux. >>>> >>> >>>Simon, Long, >>> >>>did you get a chance to run some tests with this? I have ran some tests on Azure L80s_v2. With 10 NVMe disks on raid0 and formatted to EXT4, I'm getting 2.6m max IOP= S with the patch, compared to 2.55m IOPS before. The VM has been running stable. Thank you! Tested-by: Long Li >>> >>>-- >>>Vitaly