From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=90.155.92.199 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793265110; b=HyI9oMmY1hsYHhqjpuuO0iodfAGikLxdq9AmSEAD8rRT4kpNuQOaAOvfxJxc2yvK1dlI VFSYR0ggDMucp8Wp0RG53XCMwq/2ho+ZSrAx2CBnJTJo4p3+b4AQCKolRZx/Mpck75ZRr +6zpqfHUVaovxboaG85RONafdXKI/SdL92ry8YIPnqVu1TunAt/Mo6Y6zrxqZvevvNMji lw3ffFzWR2DbLWQuXuID13OM8OHW0AOnJhM6/ULuTTj5YvAtBJq+5AOd+HqQHXG/KhNnH D+18r5pNmoNogGUcIU4hy2tldcCWnQfgIWNiSk88tZpfVhC03SVpV3bcYV3UQTPVW6w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793265110; h=DMARC-Filter:DKIM-Signature:Received:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=nVGF9duES+9fB49cpyOWp9tosy1i7wv8q/sahpSrBB8=; b=1pCeWRBOfzRsP6bEksw3tuvWY/LFmDmdT9UZecd9g8soUi01mWvzKvG5jKPHUexDQu3z HpZQ3EFE9y9OpAOpxaLE5SAhikSR7dxx1zZgDWZY4BoNVQmtzGNvWdwiRSfICoGXRUqvr MndfxzujGmW3rS7yyxpcXeHRalc23g8MTGzZHyin2Cux3joKdZ60XDNLQ3hB1j2iphXrN ZFZQaXFEZQYVNtKeuKImR6uJQ4p8A8uHdcglyN1IQy20n11LDE7DjajNZsL4VY2V7BN+e xtCfOPR1+WJaD8iRRqBzoyUFXWUg++XcNWakO0itB9AROpxviKbn9Fh64U041eJ3xJw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=JFodSFw1; arc=none smtp.remote-ip=90.155.92.199 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4730A606A31C; Thu, 29 Oct 2026 09:11:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 4730A606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=desiato.20200630 header.b=JFodSFw1 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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; bh=nVGF9duES+9fB49cpyOWp9tosy1i7wv8q/sahpSrBB8=; b=JFodSFw1zO5piOH0gPmQOJri9N M1O5oLsp5FB9kZezITLco0/xVVPqjjyx/4cG4048S+TaqGu6daKORv3xlduL81TFbV+mxvM8ziwbl FGcWHWBPIsssGzq6BLlEfxHqnhqbUO4b2tkZ/4IZwjp3QuDNSCQykq6WZTzuSYDIRD+BeCEnycs7k n3IM2K9bRxXO0M5CjYaAiCFFsfX6gwapQlt84OEcutSZAoyZBNh0wRnnYvaCicUjZo34mUx6q/dWT l2Cm00h2Al45gll7Gktdaa0xUnGEY+5BgGWOAEm6zji3SEISHxCm9XuLtqkOQY79BfgXYsd24EGQ/ ZLSI1XiQ==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMMAg-0000000GoJ4-2tyA; Thu, 29 Oct 2026 09:11:42 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 25CBC300329; Thu, 29 Oct 2026 10:11:41 +0100 (CET) Date: Thu, 29 Oct 2026 10:11:41 +0100 From: Peter Zijlstra To: Matt Turner Cc: Richard Henderson , Magnus Lindholm , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH 0/5] alpha/perf: add ProfileMe sampling Message-ID: <20261029091141.GG1779021@noisy.programming.kicks-ass.net> References: <20261028-alpha-profileme-v1-0-d44b52bf2500@gmail.com> X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261028-alpha-profileme-v1-0-d44b52bf2500@gmail.com> On Wed, Oct 28, 2026 at 02:09:29PM -0400, Matt Turner wrote: > The 21264 from EV67 on, and the 21364, have a second performance counter > mode, ProfileMe, alongside the Aggregate mode that the driver uses today. > An Aggregate mode sample reports the PC where the overflow interrupt was > taken. On an EV7 that is anywhere from 15 instructions before to 12 > after the one that overflowed the counter, which makes perf annotate > output close to useless. In ProfileMe mode the CPU picks one fetched > instruction, follows it down the pipeline, and reports its PC along with > what happened to it: whether it retired, whether it trapped and why, > whether it was a mispredicted branch, stalled before map, or was killed > on a wrong path, and what PCTR1 counted while it was in flight. Isn't this the thing that ended up as AMD's IBS?