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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 AF72EC48BC2 for ; Fri, 25 Jun 2021 08:15:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 93466613FD for ; Fri, 25 Jun 2021 08:15:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229900AbhFYIRi (ORCPT ); Fri, 25 Jun 2021 04:17:38 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.85.151]:23671 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229748AbhFYIRg (ORCPT ); Fri, 25 Jun 2021 04:17:36 -0400 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-42-I7doZoJKNZWecWq3x0a12w-1; Fri, 25 Jun 2021 09:15:10 +0100 X-MC-Unique: I7doZoJKNZWecWq3x0a12w-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Fri, 25 Jun 2021 09:15:10 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.018; Fri, 25 Jun 2021 09:15:10 +0100 From: David Laight To: 'Jens Axboe' , Olivier Langlois , Pavel Begunkov , "io-uring@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v4] io_uring: reduce latency by reissueing the operation Thread-Topic: [PATCH v4] io_uring: reduce latency by reissueing the operation Thread-Index: AQHXaVtl2q0tMJQtUkiOWyGROZvBO6skYO6g Date: Fri, 25 Jun 2021 08:15:10 +0000 Message-ID: References: <9e8441419bb1b8f3c3fcc607b2713efecdef2136.1624364038.git.olivier@trillion01.com> <16c91f57-9b6f-8837-94af-f096d697f5fb@kernel.dk> In-Reply-To: <16c91f57-9b6f-8837-94af-f096d697f5fb@kernel.dk> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: base64 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org RnJvbTogSmVucyBBeGJvZQ0KPiBTZW50OiAyNSBKdW5lIDIwMjEgMDE6NDUNCj4gDQo+IE9uIDYv MjIvMjEgNjoxNyBBTSwgT2xpdmllciBMYW5nbG9pcyB3cm90ZToNCj4gPiBJdCBpcyBxdWl0ZSBm cmVxdWVudCB0aGF0IHdoZW4gYW4gb3BlcmF0aW9uIGZhaWxzIGFuZCByZXR1cm5zIEVBR0FJTiwN Cj4gPiB0aGUgZGF0YSBiZWNvbWVzIGF2YWlsYWJsZSBiZXR3ZWVuIHRoYXQgZmFpbHVyZSBhbmQg dGhlIGNhbGwgdG8NCj4gPiB2ZnNfcG9sbCgpIGRvbmUgYnkgaW9fYXJtX3BvbGxfaGFuZGxlcigp Lg0KPiA+DQo+ID4gRGV0ZWN0aW5nIHRoZSBzaXR1YXRpb24gYW5kIHJlaXNzdWluZyB0aGUgb3Bl cmF0aW9uIGlzIG11Y2ggZmFzdGVyDQo+ID4gdGhhbiBnb2luZyBhaGVhZCBhbmQgcHVzaCB0aGUg b3BlcmF0aW9uIHRvIHRoZSBpby13cS4NCj4gPg0KPiA+IFBlcmZvcm1hbmNlIGltcHJvdmVtZW50 IHRlc3RpbmcgaGFzIGJlZW4gcGVyZm9ybWVkIHdpdGg6DQo+ID4gU2luZ2xlIHRocmVhZCwgMSBU Q1AgY29ubmVjdGlvbiByZWNlaXZpbmcgYSA1IE1icHMgc3RyZWFtLCBubyBzcXBvbGwuDQo+ID4N Cj4gPiA0IG1lYXN1cmVtZW50cyBoYXZlIGJlZW4gdGFrZW46DQo+ID4gMS4gVGhlIHRpbWUgaXQg dGFrZXMgdG8gcHJvY2VzcyBhIHJlYWQgcmVxdWVzdCB3aGVuIGRhdGEgaXMgYWxyZWFkeSBhdmFp bGFibGUNCj4gPiAyLiBUaGUgdGltZSBpdCB0YWtlcyB0byBwcm9jZXNzIGJ5IGNhbGxpbmcgdHdp Y2UgaW9faXNzdWVfc3FlKCkgYWZ0ZXIgdmZzX3BvbGwoKSBpbmRpY2F0ZWQgdGhhdCBkYXRhDQo+ IHdhcyBhdmFpbGFibGUNCj4gPiAzLiBUaGUgdGltZSBpdCB0YWtlcyB0byBleGVjdXRlIGlvX3F1 ZXVlX2FzeW5jX3dvcmsoKQ0KPiA+IDQuIFRoZSB0aW1lIGl0IHRha2VzIHRvIGNvbXBsZXRlIGEg cmVhZCByZXF1ZXN0IGFzeW5jaHJvbm91c2x5DQo+ID4NCj4gPiAyLjI1JSBvZiBhbGwgdGhlIHJl YWQgb3BlcmF0aW9ucyBkaWQgdXNlIHRoZSBuZXcgcGF0aC4NCg0KSG93IG11Y2ggc2xvd2VyIGlz IGl0IHdoZW4gdGhlIGRhdGEgdG8gY29tcGxldGUgdGhlIHJlYWQgaXNuJ3QNCmF2YWlsYWJsZT8N Cg0KSSBzdXNwZWN0IHRoZXJlIGFyZSBkaWZmZXJlbnQgd29ya2Zsb3dzIHdoZXJlIHRoYXQgaXMg YWxtb3N0DQphbHdheXMgdHJ1ZS4NCg0KCURhdmlkDQoNCi0NClJlZ2lzdGVyZWQgQWRkcmVzcyBM YWtlc2lkZSwgQnJhbWxleSBSb2FkLCBNb3VudCBGYXJtLCBNaWx0b24gS2V5bmVzLCBNSzEgMVBU LCBVSw0KUmVnaXN0cmF0aW9uIE5vOiAxMzk3Mzg2IChXYWxlcykNCg==