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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS autolearn=ham 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 08D70C67863 for ; Fri, 19 Oct 2018 00:27:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AEAEE2087A for ; Fri, 19 Oct 2018 00:27:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="XXlMQ+U2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEAEE2087A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbeJSIbC (ORCPT ); Fri, 19 Oct 2018 04:31:02 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:36548 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725910AbeJSIbC (ORCPT ); Fri, 19 Oct 2018 04:31:02 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9J0NbH1006032; Fri, 19 Oct 2018 00:27:05 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=gZUWIHRxBCWO/Hu9Bcek6ZhqmzPDzzIWZIqGiyhJ8bA=; b=XXlMQ+U2TRJ0SOsqSmeNECVkYyUU+0PvU6vQQ8T2PbEFOhB66vwC3243q9M3O2oy9tne 8HxXGnWRvLpwscu25tP9HPaqiNZcSNLa/wB+dD/1EJaNTyqtq+H0cqzwjqQzKyLkVkD1 kQWq9vOv2dzQqhshrr3ywFu96gMgpqokc86o23XchTnJn1bqZ8u4lXjopm3uwTej+jDB 1v/7oyq48W3aubEm6IgKDJTMDgBwPMD5MlHzSyanhqShWLt/DjuvuJDk8I4FFt/tdGlq h7ZlmENEp4eob5Or2rnO9jCdMxiD/yYaMBWYNo7P54rMCaXR4RIVyd/zS1h7BVUwaEUP ug== Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by aserp2120.oracle.com with ESMTP id 2n38nqhf8r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 19 Oct 2018 00:27:05 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9J0Qx6J028899 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 19 Oct 2018 00:26:59 GMT Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w9J0QxqY002191; Fri, 19 Oct 2018 00:26:59 GMT Received: from [10.132.91.175] (/10.132.91.175) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 18 Oct 2018 17:26:59 -0700 Subject: Re: [RFC 00/60] Coscheduling for Linux To: =?UTF-8?Q?Jan_H=2e_Sch=c3=b6nherr?= , Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org References: <20180907214047.26914-1-jschoenh@amazon.de> From: Subhra Mazumdar Message-ID: Date: Thu, 18 Oct 2018 17:26:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20180907214047.26914-1-jschoenh@amazon.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9050 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=923 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810190002 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jan, On 9/7/18 2:39 PM, Jan H. Schönherr wrote: > The collective context switch from one coscheduled set of tasks to another > -- while fast -- is not atomic. If a use-case needs the absolute guarantee > that all tasks of the previous set have stopped executing before any task > of the next set starts executing, an additional hand-shake/barrier needs to > be added. > Do you know how much is the delay? i.e what is overlap time when a thread of new group starts executing on one HT while there is still thread of another group running on the other HT? Thanks, Subhra