From nobody Thu Jan 29 21:09:47 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 4f2Bc61LF7z6Q0v4; Thu, 29 Jan 2026 21:09:58 +0000 (UTC) (envelope-from olce@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (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 4f2Bc56YZqz46X0; Thu, 29 Jan 2026 21:09:57 +0000 (UTC) (envelope-from olce@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1769720997; 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=kEBvxMv1t2XXR+/+yde00l+erHpv28/1JyNmjzPwuqU=; b=h7yOuEf8g90TdfnMrI6rZXIR+mLJHEl28Qwgtkf9F3ysLDu5XHsPjr35og3qGMcvNG22BN xfmC/izufE0obCYG5xBAD/cX4/j/3nbxl5FBQJiYbg9kYjv6ubDJFTFnCAz01lzeCM2UF2 x8Uyn31Y9yu+/dAdmVljl5XBhlZcnB2DBJ1C2d6ul7LRY4zpVXj49vO4i/XU4+ZUxkjfSl aAK+R4bbgRPBQ0JSyrirVDQwuclQBd/YdZtNC5U9k2/0H5/ldyDB2gP4YjzYCW40xD8MTj AIpq0CKpM8naao0wQJz0SDbatDv5QdeNEvmocQ6S00E0RZ/MSZsRnLmBWhfOeA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1769720997; a=rsa-sha256; cv=none; b=SslCWX5zTbYdYEUVSCkYWjUx+DWe5pfkV7ZuYJUX58HB2LoxlH9Cq4cCny4eiBadA2qYSQ j05rQZTs2N4O0fsfV1UmSe/lg8hjGQfnv0bDYe5uoSy6A+63dqF8Sf25+NnIXA+p09b61J 4oNCEEfXgA3rpa0fbi79067LJgOB5MJX+3kbEHztlitbkMQS+SMUJoIBHLItsUXlEPq+L5 +LaLfLny7Pm2K1Wo9kDGUW3mFCfQtLHk0yGEPtmf1J4Ft/OTHfsweVZcN4FRum4QieSRMM w/WwIMeGm7UHxsDL4NjFI+eSfIiD2br6roKQ4q3jsiobJB8HDySzNGavNw2sXQ== 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=1769720997; 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=kEBvxMv1t2XXR+/+yde00l+erHpv28/1JyNmjzPwuqU=; b=ldWKgS6zksWNvEnN3Kp/JtVHi6kZ+JMIJ4w3ArOVCQCeW7LvWA4yh19wGpPDHhpVBnpeqE hrsuZLz7zDwMkfxwmtR7F09kP1fWRRI2zjFLAJpKCKO756mjvXxgkY9RkEB7rveLDUc1OT zURf0wej+TFRIQ9w9lMnyB8wK596ztsg6kJ4O/w7ONjKJZuZ+jSJ2plCxJ0E+bY7zpCe1o YHY03/k6H590UBtsFZx2AhqsuFyEwEmrsKAU1yhrnVvm+g2cj6aljq4nwKyvVxExfNUWm9 FEf5km3gQwGcGbmg3Gu+hA6Y+jLKk4lXuiaFUVrRmo4QAvYo/NAEpKzKMZc/Kg== 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 4f2Bc514L9zPY3; Thu, 29 Jan 2026 21:09:57 +0000 (UTC) (envelope-from olce@freebsd.org) From: Olivier Certner To: Gleb Smirnoff , Drew Gallatin Cc: freebsd-current@freebsd.org, src-committers@freebsd.org, ShengYi Hung Subject: Re: January 2026 stabilization week Date: Thu, 29 Jan 2026 22:09:47 +0100 Message-ID: <8518827.G18vQ0XA4d@ravel> In-Reply-To: <6197e075-212f-4260-b437-902e06d1002b@app.fastmail.com> References: <2329920.sMrx5ctUpN@ravel> <6197e075-212f-4260-b437-902e06d1002b@app.fastmail.com> 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="nextPart3182097.fEyhCgFcho"; micalg="pgp-sha384"; protocol="application/pgp-signature" --nextPart3182097.fEyhCgFcho Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8"; protected-headers="v1" From: Olivier Certner Subject: Re: January 2026 stabilization week Date: Thu, 29 Jan 2026 22:09:47 +0100 Message-ID: <8518827.G18vQ0XA4d@ravel> In-Reply-To: <6197e075-212f-4260-b437-902e06d1002b@app.fastmail.com> MIME-Version: 1.0 > On Intel, and now on AMD, it seems that CPPC is far worse than powerd (*). That must depend on workloads and objectives then, since I've had the opposite experience on laptops in terms of latency. > (...) And high settings use more power. But providing better performance, or not? > So the ability to let software control frequency is something that I don't want to loose. I certainly don't have plans to remove that. When talking about recommending CPPC, I was thinking about the default value we wanted to have for the new 'machdep.hwpstate_amd_cppc_enable' tunable, but not about removing it. IMO, this tunable is here to stay (it might just change form at some point). I also encourage you to give a shot at the patch in PR 292615, in order to see how the new knobs (min & max performance, desired performance) can affect your observations, even if after what you reported that may look unlikely. For the future, we should probably eye at teaching powerd(8) about working with CPPC, so that instead of trying to set frequencies directly (which cannot really work with and basically defeats the point of CPPC) it would instead tune the desired performance value (and possibly the min and max ones as well). Perhaps with that combination we could get the best of both worlds (software + hardware tuning), at least for some workloads. -- Olivier Certner --nextPart3182097.fEyhCgFcho Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part. 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