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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 DBF28C31E51 for ; Tue, 18 Jun 2019 12:23:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2BBD20873 for ; Tue, 18 Jun 2019 12:23:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="F/I7R90c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729089AbfFRMXd (ORCPT ); Tue, 18 Jun 2019 08:23:33 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:33800 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725955AbfFRMXd (ORCPT ); Tue, 18 Jun 2019 08:23:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=kNi3XQTa/+ngtDRDU/l4s27s4LRCp411GOAAso5qJSY=; b=F/I7R90ceFW+vmCgY+WJQOJbA pvhriAwL77+n2hr/V0SY5YVh+q6jxecKm0igOHx2o2ZXLcgUUe5AZaKu4Przn8gyt5lIOUx+H2PW2 bTH+beQOHI67CgnkH7JxSkMQSzaD1zf440yUCztXudXE14U52SBXNbdnzu7ZNjw+4a4Q881/0VSOC Jr8HGqVj2tMSqEhghpDjzVTNXJETzsInnYJ9afOnarjb3mIQNb0D1cnnGFpGKTAHlkYAD9SWSpakD tiMq3I6gpclW9GBKx8lzKnrz+N/n1h9tPgX9kUf9vdaXWEFlvZvHT2mGOX04TofqkeYY9R4OJa2ho BQXbBINNw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hdD99-0004ua-Ho; Tue, 18 Jun 2019 12:23:31 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4F8302076F70F; Tue, 18 Jun 2019 14:23:29 +0200 (CEST) Date: Tue, 18 Jun 2019 14:23:29 +0200 From: Peter Zijlstra To: Mukesh Ojha Cc: linux-kernel@vger.kernel.org, Raghavendra Rao Ananta , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Alexei Starovoitov Subject: Re: [PATCH V4] perf: event preserve and create across cpu hotplug Message-ID: <20190618122329.GE3419@hirez.programming.kicks-ass.net> References: <1560337045-13298-1-git-send-email-mojha@codeaurora.org> <1560848091-15694-1-git-send-email-mojha@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1560848091-15694-1-git-send-email-mojha@codeaurora.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 18, 2019 at 02:24:51PM +0530, Mukesh Ojha wrote: > Perf framework doesn't allow preserving CPU events across > CPU hotplugs. The events are scheduled out as and when the > CPU walks offline. Moreover, the framework also doesn't > allow the clients to create events on an offline CPU. As > a result, the clients have to keep on monitoring the CPU > state until it comes back online. > > Therefore, That's not a therefore. There's a distinct lack of rationale here. Why do you want this?