From nobody Thu Jan 29 08:47:48 2026 X-Original-To: freebsd-current@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4f1t7y1YZXz6Q8Nv; Thu, 29 Jan 2026 08:47:58 +0000 (UTC) (envelope-from olce@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4f1t7y0Wy5z3FG6; Thu, 29 Jan 2026 08:47:58 +0000 (UTC) (envelope-from olce@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1769676478; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GbHPpDD957AR80CenoB27A9I5jcl5CBhCIbujVs0oaY=; b=YQO0UejBWiPXCn0AwFeh/XElQD0ktLB+pzrpBZ3X+1qRhmcpdPCPCzSFNKjLA6R0Pw+0p7 zTBQaXhwY+evWjn22uz0+Wgih3O8l4eubaNeMdOVyH60Xskqr98oouUwXX+DwaJj649lhY uuIkiBpXE3pKgcPqEiurGsNTGnKUeLB1sobPhlyDDPN0grUGjXP2vqVPfQVnuMQ2lN86P/ GtWZdWTx4qoAneaaKxtHkE4kWQHoE/WSMF1/ijk9r7TGgiTvgxIjHKBYisQoO+ovTZDCZh nGnbc1Ej1tkjd/O07fmLnpQqXAxHD6NsJvUiI1pIHCsGn+t+8jslMRmmtNm92w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1769676478; a=rsa-sha256; cv=none; b=kO0ShUA/bYmrh24yUZ14Svb/TEnvzltKxw7UNLqIgu/5mzUi+PNIawqc3h5QbU6FtCAXxE ESTreMKegNGi3lxyq5jJ2zr08R1KElGHVQSq8f/3lFQ4OGIvObiOlJMhyUzCnsjQZioT4d MjEhYG2s2alzAsG0V9+iUm/G+R66iGV5j2rthtNDQOENBguA2BxttJnSI66kpRhf5ORL66 CJhZJtGEEbOb5jJAi8wY7Nmdt0qRpMl/KazMWikK28+dSx3WtO1xNNpN+CvqbunuvhnNfb fa0BN854zo5ouOhWeWSEaxYucBFJ5dBLV2cb7ifC+1UgsK5jHGAky/0lAyYgLA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1769676478; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=GbHPpDD957AR80CenoB27A9I5jcl5CBhCIbujVs0oaY=; b=Syp3Wm3+5/Aa9yFA5tOnCc+8UKfVzQZJONQcxfU4qEk/mSfxDLuXDCpp78KtQUcrCOReTy 5eDpLiYoY1e2hROw7uzPn9QV1vBc2pmxq7S8xxMYuJGoS/I0li3DsMsDDnqtfEHq4QwdUC ZWB2D9OUtm1Tqvd8pXc4SJL6JhaCjXUHWHjIOVxzPgG+/AAW6t8pJSvYQKNVS5zSqwKASY 5tXDxpWdWUi32busMa2ItaP5ByjK04EscXePVFa2M1P6px4koCZgupXn5WBG90digvG5ce OT3dRAtHTSjYSwoJOo/wj23eFd8On7zshM7t/cQHT2ApAnh5uzXyvckBo6xBYg== Received: from ravel.localnet (aclermont-ferrand-653-1-222-123.w90-14.abo.wanadoo.fr [90.14.66.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: olce/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 4f1t7x2kMnz7lC; Thu, 29 Jan 2026 08:47:57 +0000 (UTC) (envelope-from olce@freebsd.org) From: Olivier Certner To: Gleb Smirnoff Cc: freebsd-current@freebsd.org, src-committers@freebsd.org, ShengYi Hung Subject: Re: January 2026 stabilization week Date: Thu, 29 Jan 2026 09:47:48 +0100 Message-ID: <2329920.sMrx5ctUpN@ravel> In-Reply-To: References: List-Id: Discussions about the use of FreeBSD-current List-Archive: https://lists.freebsd.org/archives/freebsd-current List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-current@FreeBSD.org MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart3263635.ZmR5Pbtf01"; micalg="pgp-sha384"; protocol="application/pgp-signature" --nextPart3263635.ZmR5Pbtf01 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8"; protected-headers="v1" From: Olivier Certner To: Gleb Smirnoff Subject: Re: January 2026 stabilization week Date: Thu, 29 Jan 2026 09:47:48 +0100 Message-ID: <2329920.sMrx5ctUpN@ravel> In-Reply-To: MIME-Version: 1.0 Hi Gleb, > 2) The AMD CPPC switched on by default instead of Cool`n'Quiet caused problems on > certain hardware. For laptops see bug 292615. > At Netflix A/B test we discovered that CPPC mode reports wrong frequency levels > to powerd, which results in reduced performance. > This problem is still not resolved. ShengYi will be, AFAIK, mostly unavailable for at least a month, so I'm handling the AMD CPPC problems (actually, I've done some part of the initial work as a reviewer and by proposing changes to it). I've been having some mail problems in the past days, so sorry if I missed something, but it's the first time I'm hearing Netflix experienced a problem caused by the new AMD CPPC. If powerd(8) tries to set frequencies to balance performance/efficiency (as it always has AFAIK), it is in effect incompatible with CPPC, both this new AMD implementation and the already existing Intel one. They do not allow to set frequency but just report the current real frequency which is *dynamic*, i.e., it can frequently change even for non-changing CPPC control values (that's the entire purpose of CPPC). In the future, we'll probably want to add support of CPPC to powerd(8). For now, it's either CPPC or powerd(8) (as for Intel), and a priori I'd recommend switching to CPPC entirely (once we have finished with the potential problems here). For pressing production issues, in the meantime you can set the 'machdep.hwpstate_amd_cppc_enable' tunable to 0 to force using the "manual" P-states that powerd(8) can manipulate. Please help us by intervening in bug 292615, adding comments about your problems and findings (or mail them to me if they must stay confidential), and please read the latest comments, apply the latest patch and play with the different knobs as explained there. Depending on your feedback, we may be able to provide more specific guidance. If CPPC mode reports a wrong frequency (how do you tell?), please comment there also, and depending on first analysis, we'll see if we want it to be a separate bug or not. Thanks and regards. -- Olivier Certner --nextPart3263635.ZmR5Pbtf01 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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