From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yx1-f49.google.com (mail-yx1-f49.google.com [74.125.224.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 12C4F1F4611 for ; Sun, 11 Jan 2026 04:53:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.49 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768107228; cv=none; b=SUxPHaVC+5P2+Vs7XUQeLs5cJwDFL7xLeZomrQ2jdJrnMA6LzJCXx8+cPnZzxJ3jiBYAfycf95EfpnHTBoUGu7evREnt/2jJE+3K7/OOF0gEhBkGt7xeBbAhWADXZKLVVOwXX6d0p96PqKMqbFAn8PQ1OUjAcVDo9//T1QGNtPw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768107228; c=relaxed/simple; bh=FKIKTBZ0GsN4rm/M9grFO1cXmdRTqeRGz0314M/ltwk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Tea27kcPZIfYH8fh8eOnmfw4plPwyhP7/0uR8FvgQbhkit8xL5Szi0U3jzJI/wnxkNRQ4h6j1zAoWuvVDKoB5DwI6tkc6dXZrLEY1GtWQ1inMwmZRqMvoK3P97KxbF1xV6QwSmFxvH4IYeCKzq3jsigGfWdmBvBvOqN+clVhXEE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=V7eFud5L; arc=none smtp.client-ip=74.125.224.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="V7eFud5L" Received: by mail-yx1-f49.google.com with SMTP id 956f58d0204a3-6446c924f9eso5006038d50.1 for ; Sat, 10 Jan 2026 20:53:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1768107226; x=1768712026; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=oRTKAtfTpzFTDAQuznCEfe1KGiZpT38bizObLyToCRI=; b=V7eFud5LrfrkgwNVlMeICyRuXe2QrvWQ/S7dyAzTvjvemj5+QUaZWaA5VgrAh0KcIB eLlc76qA4MAAxzVTrLwHxkBsj491CDgsg+rD4ctHaleCH8iwoupOqAoU7BfMO/kdh0/7 Wsk7Z+PkN413IdNew4pu/kCws46l5bndSC7IbruRQvWYCW/vUEQBNvlUZjZHE9ETB0qW AeafvioZ8Bxp68YKWGGFNDd19AUfBYjMIUJU8kilEuVToPfmFv7AyRTi703YjjKBEbcb nHTkh7Uw0UHsjffry/sgoS420DOs/Ouf8SYb3vexhMItcmkLXuOmEg28C9yA8aCV3K7D 4Zyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768107226; x=1768712026; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=oRTKAtfTpzFTDAQuznCEfe1KGiZpT38bizObLyToCRI=; b=TGpWI0N1XST1epsj5z1oSHC9y8yvEGGma7RYe8VskPy3HoZXhrD6a0OZELEznyeOdV wWUBEsBaWN7vpegia9iprPGsopVPfpHsH8DnaAbWDz+bmQ+zD5Xr7NHks/rM+xjTEiqO IcXIub3lMK/EIrRqlOzONTiy0jZJY7J1n2WQv6+QzaXRfujavURzTncqvdRfNmdD1DgD Evldne6LELCe797IKm68jtic8jLnrX83wrgzbhZegDoV3NGS3c+2RiyREn+EfbI7/QP+ pP7DGYYvuP/XMDhfez64/JtHUhHl/hj6O5NFd9dRaeFU6MsJFNsVkr46+OngZxSWpP2K 5Tog== X-Gm-Message-State: AOJu0Yz8DY6Qkq3kzf0s4jCELYwcz5Qw0O5JdQbK4CDrHsIUecX/BaKZ t4M6okP28Ebjj+Weyr0GN89YIRY8lZaCiUrp3NyFIQiTuklR7j5ciWD6 X-Gm-Gg: AY/fxX6e89ZyEaPatoj4p1rBfaiu+Xn35Gvlf8zqxNt+PLw/lx4wBt/xaS2H3pB0F+u reUbgHQogfxnGBS0/gGY/8t99mnGIYasDw4D+Bpv6b9nkAS5nOsVbjuCa42YRcBDDtNfrPxPY0f TUjAVk1k1kRnUpMUQDXGKSAbkHep58WHJuRkR5WlaA50SSl51kmQ17fIsZVuKmZIxTV72YIw6wu /cS+BGGiePCmCAA+EilAkkU8i3Ge4JfP5SKVodXz26ri7etl+9/bOx+4n+OhwApiT4GiBOOAPI+ JUCtDBR8/n53tSjNW+NxWBEdBU9wSQTKY+JpA+PQrADSXhNAF0jo3CvqdtUsiC8CDkiqgHdfRHV 4zI8kLThto5hs+gJjUoWSlSue/QhCb6735Ie5MUP44FKJZdvUXkQ+nE23NvPvjODpcY8JYPXnhh P9H8/PDx7V3AKJ95N3G+olhjJltwg= X-Google-Smtp-Source: AGHT+IHohfOhEFk4Mf7LjLQGgnKTKKpnpcw8p3//gTfyYfqXoeDlZ3mCjB5GPCu04MV4ruzVOOQv4A== X-Received: by 2002:a05:690e:1911:b0:644:46c8:b990 with SMTP id 956f58d0204a3-64716ba14damr11345968d50.32.1768107225992; Sat, 10 Jan 2026 20:53:45 -0800 (PST) Received: from ?IPV6:2600:6c56:7d00:582f::64e? ([2600:6c56:7d00:582f::64e]) by smtp.googlemail.com with ESMTPSA id 956f58d0204a3-6470d89d510sm6556709d50.16.2026.01.10.20.53.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 10 Jan 2026 20:53:45 -0800 (PST) Message-ID: Date: Sat, 10 Jan 2026 22:53:43 -0600 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] intel_pstate: CPU frequencies miscalculated/incorrectly detected on Arrow Lake hardware To: Aaron Rainbolt , srinivas.pandruvada@linux.intel.com, lenb@kernel.org, rjw@rjwysocki.net Cc: linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, kernel-team@lists.ubuntu.com References: <20250517223323.6e13bf58@kf-m2g5> Content-Language: en-US From: Russell Haley In-Reply-To: <20250517223323.6e13bf58@kf-m2g5> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/17/25 10:33 PM, Aaron Rainbolt wrote: > We have tested three systems with Arrow Lake CPUs, and all of them > report incorrect max and base frequencies. Two systems have Ultra 9 275 > HX CPUs, and one has an Ultra 5 225 H. The problem occurs with both the > Ubuntu 6.11 kernel and the 6.14.6 mainline kernel. > > How these values are misreported appears to depend on the CPU. On the > Ultra 9 275HX systems when running Ubuntu’s 6.11.0-1015-oem kernel, the > max reported frequency on a golden core is 5000000; however, the CPU > spec says it should be 5400000. In contrast, on an Ultra 5 225H system, > the max reported frequency on a golden core is 6200000; however, the > spec says it should be 4900000. > > This bug is troublesome to end users because many CPU monitoring apps > will report the CPU is running quite a bit slower or faster than the > spec. Tools such as cpupower-gui, cpufreq-info, and cpufreq-set all > show incorrect values because they read cpuinfo_max_freq and > base_frequency, and write scaling_max_freq values in > /sys/devices/system/cpu/cpufreq/policy* directories. > > The following bash script shows the incorrect values read from the > cpuinfo_max_freq and base_frequency files. It also shows how the actual > max frequencies attained are as expected. The example values shown come > from an Ultra 9 275 HX CPU. > > echo; echo '== BEGIN =='; > echo 'Ensure turbo is on'; > cd /sys/devices/system/cpu; > echo '0' |sudo tee intel_pstate/no_turbo > /dev/null; > if grep -q '0' intel_pstate/no_turbo; then echo 'Turbo is on'; fi > > echo; echo 'Find top 2 golden cores'; > cd /sys/devices/system/cpu/cpufreq/; > grep . policy*/cpuinfo_max_freq \ > | awk -F: '{print $2" "$1}' |sort -rn | head -n2; > #> 5000000 policy2/cpuinfo_max_freq > #> 5000000 policy3/cpuinfo_max_freq > > echo; echo 'Confirm misreporting: per spec, this should be 5400000!'; > grep . policy2/cpuinfo_max_freq; # 500000 > > echo; echo 'Confirm misreporting: per spec, this should be 2700000!' > grep . policy2/base_frequency; # 2500000 > > echo; echo '# Run a CPU benchmark now, then press [ Enter ] to see top 3 freqs.'; > echo 'This will take 6 seconds to complete.'; > read -r -p '# You should see that the freqs match the CPU specs. ';\ > for i in {0..5}; do > grep . policy*/scaling_cur_freq | awk -F: '{print $2" "$1}'; > sleep 1; > done |sort -rn |head -n3 > #> 5400000 policy2/scaling_cur_freq > #> 5320159 policy2/scaling_cur_freq > #> 5241886 policy3/scaling_cur_freq > > echo; echo '== END =='; echo; > > The actual results, when running the above script, shows the > cpuinfo_max_freq and base_frequencies values do not match those > specified by Intel. With the 6.11.0-1021-oem Ubuntu Kernel, we see the > following: > > | Turbo? | Core | Freq (spec) | Freq (report) | Freq (actual) | > | Yes | P | 5.4 GHz | 5.0 GHz | 5.4 GHz | > | No | P | 2.7 GHz | 2.5 GHz | 2.7 GHz | > | Yes | E | 4.6 GHz | 4.6 GHz | 4.6 GHz | > | No | E | 2.1 GHz | 2.1 GHz | 2.1 GHz | > > We have verified the cores are operating at their specified frequencies > by running a demanding CPU benchmark while graphing frequencies with > KDE System Monitor, on all 3 systems. This tool appeared to graph > scaling_cur_freq values. Notice E-cores appear to be correctly > reported. Also, all systems misinterpret values written to > scaling_max_req with the apparent same error deltas: on the Ultra 9 275 > HX, setting this value to 5000000 results in actual max frequencies of > 5400000. Setting it to 2500000 results in max 2700000. Setting it to > 1650000 results in max 2100000. > > The behavior with the 6.14.6 kernel is worse than with 6.11, with all > values under-reported. Actual frequencies were not tested on 6.14.6: > > | Turbo? | Core | Freq (spec) | Freq (report) | > | Yes | P | 5.4 GHz | 3.9 GHz | > | No | P | 2.7 GHz | 2.0 GHz | > | Yes | E | 4.6 GHz | 3.3 GHz | > | No | E | 2.1 GHz | 1.5 GHz | > > Is it possible the math currently used for calculating CPU frequencies > is no longer correct for Arrow Lake CPUs? This seems similar to the > issue that was fixed by commit f5c8cf2 (cpufreq: intel_pstate: hybrid: > Use known scaling factor for P-cores). It also sounds similar to a situation I reported here [1]. My machine is a desktop 265K in an ASRock motherboard. The problem was fixed when I updated the firmware to version 3.11, which contained microcode 0x11a. That firmware was released in September. The latest 3.15 from Dec 29 contains microcode 0x11d. You can check by grepping dmesg for "microcode". 1. https://lore.kernel.org/all/53027db5-f750-4b6f-8ac5-a849dff2524b@gmail.com/