From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2A3873A9630 for ; Mon, 24 Aug 2026 09:06:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787562376; cv=none; b=gmNThuONcdfp3ElTZ97wSFlDE7fY1JlkMcCFwgmDLqv+hyrwzcd/fcWneCP0klH9u5uSvKN9HThzM1tzytuHHsQV/WGnISjL8iKskAMWnGfZsw3essLjbw/m4x9QC0k3YM6EUYlj0++/RgkeNfpgZM/GgORGapiywVcHmivK1hU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787562376; c=relaxed/simple; bh=LJpj1PnQwNhmuxUpZJfJrnizhShfhA0kVDmQY+b6ELc=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=kkLhIXbnDLeMqZVMVROf7Ad8R/1vMJZpfHw0gmSLns7U09wNbtjh4xJpqxaXwfKm2SMGSLWMjUZPdESe+vmZRS9YqQT6/VHBsi5r6WhF9lzRp018uV5Zl8lwb/6BFKV0xSSv4Ey7YCWSsq5YBBy/kWDpxTPUalAFmqOI9XZnPIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MFmdhfRK; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MFmdhfRK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9809B1F000E9; Mon, 24 Aug 2026 09:06:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787562374; bh=LJpj1PnQwNhmuxUpZJfJrnizhShfhA0kVDmQY+b6ELc=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=MFmdhfRK7KYE7B1rWsV2Ed6ufTByrfE3iKmtu+HKpMYltG4r92c2boyVNmyJUf5XN AF/f39eTLRNm4lb0ZhSlNR2PiDbaIbTRs566W/eHfMkonKOFsBa5owBc2KIzmwK0A4 R9vOlByiAyIIA1JWfPIm2fmSs+he+PNEFHXeHsrkLWyyS4OFmG2nNrR4wDloDVOVAr SdaAOy1ehvSIvTizrTHhMmbZDKDlQrKFTVxig9Iq8NGxSeQvIcjVCNAtq5Xl4BabIo pYKItY+l1miyN6DuXuVll32tvcip+DOjhLZg/scx1MUMORNbKMI5fC7/2s0L7nNvQx 8LzptxFQLz9Mg== From: sashiko-bot@kernel.org Subject: Re: [RESEND Patch v10 22/23] perf/x86: Activate back-to-back NMI detection for arch-PEBS induced NMIs Reply-To: sashiko-reviews@lists.linux.dev To: "Dapeng Mi" Cc: linux-perf-users@vger.kernel.org In-Reply-To: <20260824082731.1013973-23-dapeng1.mi@linux.intel.com> References: <20260824082731.1013973-1-dapeng1.mi@linux.intel.com> <20260824082731.1013973-23-dapeng1.mi@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 24 Aug 2026 09:06:14 +0000 Message-Id: <20260824090614.9809B1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > When two or more identical PEBS events with the same sampling period are > programmed on a mix of PDIST and non-PDIST counters, multiple > back-to-back NMIs can be triggered. >=20 > The Linux PMI handler processes the first NMI and clears the > GLOBAL_STATUS MSR. If a second NMI is triggered immediately after > the first, it is recognized as a "suspicious NMI" because no bits are set > in the GLOBAL_STATUS MSR (cleared by the first NMI). >=20 > This issue does not lead to PEBS data corruption or data loss, but it > does result in an annoying warning message. >=20 > The current NMI handler supports back-to-back NMI detection, but it > requires the PMI handler to return the count of actually processed events, > which the PEBS handler does not currently do. >=20 > Thus, modify the PEBS handlers to return the count of actually processed > events, thereby activating back-to-back NMI detection and avoiding the > "suspicious NMI" warning. >=20 > Suggested-by: Andi Kleen > Signed-off-by: Dapeng Mi Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260824082731.1013= 973-1-dapeng1.mi@linux.intel.com?part=3D22