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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B51CFC433F5 for ; Tue, 12 Oct 2021 08:22:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 863AF60E74 for ; Tue, 12 Oct 2021 08:22:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 863AF60E74 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=MCgmTzofr636n4PgskcyS8eWrNthGdi01eXhGe4vV/s=; b=q21P839IVTJtU3 O99uOjnWI4jIqCWgVUCMoLbKSEfHubcR21rdzi07VZ1WULz/St8KoWgyZmzRtNcAEY9xe239bewPL JLY5fy8dbJPWBYO+8bc8siOo9MLcyOjA6FR+gjtGowR3jtHziGNtpM6ToAoTdtSHc+9BhOdJZIHAq hx2/fTVnGIx5OKfYa17URQ6TV4LeEoq/DlxLE+eG3jW8zcIpj/LLFCxkBSNaZzznU55g48rwYC05x 5BebTKcKKalhbocPMi/+MXlxUWehY8Y5g4DHcFLbi1y36P1kOFttbfPh2n0pGOLvDEd6UiuAWy4vY NksbAbo6x990WF7Fgxzg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1maD0x-00Bz1W-38; Tue, 12 Oct 2021 08:19:59 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1maD0t-00ByzE-2D for linux-arm-kernel@lists.infradead.org; Tue, 12 Oct 2021 08:19:56 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5C27A6101D; Tue, 12 Oct 2021 08:19:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634026794; bh=lDPufYSiKyvGGDrYONfULzGOTQL591ZiKQDt8MPRrw8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=EbhrCQT6mNhvQPiAFl8cNGZj7me7jYjv8/NCbzUy/aKo5RfWSXhn4M4I78GlMhNRN pruhFBcjfGZcQkqF+4MPON1fwgpXBNmSoDzYF/fF4/0mYUDH3g6ZXPuATahOpCcOgq +q0S6w9teF4Kw+i2PtOTccVI0E/N4LIvGostQHdf+3j1mApKvEZyDRr7DlVJHOTpCE nx5qm85PGJTFzlTIBreR9gDbjD/K+a/s0oVk3UIkQOQh6bgoQImCGJ4ckusQxKlJ/D eAqfvgiMXVFt82AgIP8Y/awQPdli5FYtnaEAdAkxd4wg6pPT4RTUZVzqLF0EI5mlCy rDeHnI04DOUdw== Date: Tue, 12 Oct 2021 09:19:48 +0100 From: Will Deacon To: German Gomez Cc: Leo Yan , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, John Garry , Mathieu Poirier , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Mike Leach , linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, James Clark Subject: Re: [PATCH 4/5] perf arm-spe: Implement find_snapshot callback Message-ID: <20211012081948.GA5156@willie-the-truck> References: <20210916154635.1525-1-german.gomez@arm.com> <20210916154635.1525-4-german.gomez@arm.com> <20210923135016.GG400258@leoy-ThinkPad-X240s> <20210923144048.GB603008@leoy-ThinkPad-X240s> <1c6a3a73-27dc-6673-7fe7-34bc7fcb0a68@arm.com> <20211004122724.GC174271@leoy-ThinkPad-X240s> <6b092f13-832f-5d1d-a504-aea96c81bf17@arm.com> <20211006095124.GC14400@leoy-ThinkPad-X240s> <377b54ef-b9c0-9cfc-ef0c-0187d7c493cc@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <377b54ef-b9c0-9cfc-ef0c-0187d7c493cc@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211012_011955_184538_E67AEFAE X-CRM114-Status: GOOD ( 17.45 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 11, 2021 at 04:55:37PM +0100, German Gomez wrote: > Hi Leo, > > On 06/10/2021 10:51, Leo Yan wrote: > > On Wed, Oct 06, 2021 at 10:35:20AM +0100, German Gomez wrote: > > > > [...] > > > >>> So simply say, I think the head pointer monotonically increasing is > >>> the right thing to do in Arm SPE driver. > >> I will talk to James about how we can proceed on this. > > Thanks! > > I took this offline with James and, though it looks possible to patch > the SPE driver to have a monotonically increasing head pointer in order > to simplify the handling in the perf tool, it could be a breaking change > for users of the perf_event_open syscall that currently rely on the way > it works now. > > An alternative way we considered to simplify the patch is to change the > logic inside the find_snapshot callback so that it records the entire > contents of the aux buffer every time. > > What do you think? What does intel-pt do? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel