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x-microsoft-antispam-message-info: PuuH+Koz7mDf68WDuL2hwIx8QNuUU2OmH4RPTLpHRor14I0ykKU3oFr+0NVVvPKSdyzH5Vmt8tDgfV8Z8Zq4Q5o40f3LErqwHBD5TCArDICCCbvRe09vR48/1EeEbPkvKO+cpLhBOeIPGT2oi3EHaxg4KHis6r2HyTaSk5/p0LM= spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-ID: <427F65363C83344EBF4BA933C493CAE4@namprd04.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 7b50bb5e-bd35-4aef-046e-08d578a6ee57 X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Feb 2018 21:14:29.9971 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR0401MB1631 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2018-02-20 at 21:59 +0100, Arnd Bergmann wrote: > /* # of WCs to poll for with a single call to ib_poll_cq */ > -#define IB_POLL_BATCH 16 > +#define IB_POLL_BATCH 8 The purpose of batch polling is to minimize contention on the cq spinlock. Reducing the IB_POLL_BATCH constant may affect performance negatively. Has the performance impact of this change been verified for all affected driver= s (ib_srp, ib_srpt, ib_iser, ib_isert, NVMeOF, NVMeOF target, SMB Direct, NFS over RDMA, ...)? Bart.