From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 50E141C84DC for ; Wed, 21 Jan 2026 22:25:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769034302; cv=none; b=csDhB9NFMfeXluyCpEWwL1UtU96OeWz3c++wlR935E7tzDraVWik3rNioZ/31SMdf2rGlfB7KaaoqHBbr6vgtfuZ34NyKEv5ipdevhWc6k2B96OhrNpiZEWedPPkU2NW3pOrGFZNzKjEldD/gemH5UQPS3nT1EY03QfkzRZM8qU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769034302; c=relaxed/simple; bh=htBqagd7wv7WLkck7lQGCK3mGbrB8F5r/45p/0pVm9A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JX9B2d16EzWYZIN10H/W6G4an77qGAXLwkwyM422VJIZE4E+OqJejCadGKTiyr2IM/ibHz5T8zmfJch20LHJZlKCvbXUMawzMhdzJohxwQy4RQmU5fZn+UzAGWy/+x0Japuqni2skUpVs9FMGCWHyBcFhkGtCf6Wti2i5CnE0b0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=fRLEV1bj; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fRLEV1bj" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1769034299; 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=JisEtCd7o6MQ3h+EYWwRWC/6q6quKsN2W90F49ARass=; b=fRLEV1bjrSw1FNcgQgAOH7g6ZcYI/JnLxB3m4XRb1nndqJiHk7E1VlBScAOeZQQIv5koBf jFh35/MrwBmpv55s3K4dciqn8+HBZYL1K0Nsat3p9gvBsAn2hLM9xDZmYhG7rKYOzT0snT xKXJMop8YS18mRfmLHaVjj5cnWfQ2So= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-696-umLStBV6NNWbOOTij-Dw-Q-1; Wed, 21 Jan 2026 17:24:53 -0500 X-MC-Unique: umLStBV6NNWbOOTij-Dw-Q-1 X-Mimecast-MFC-AGG-ID: umLStBV6NNWbOOTij-Dw-Q_1769034291 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8E0C019560A3; Wed, 21 Jan 2026 22:24:50 +0000 (UTC) Received: from pauld.westford.csb (unknown [10.22.65.128]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id BDF341800577; Wed, 21 Jan 2026 22:24:46 +0000 (UTC) Date: Wed, 21 Jan 2026 17:24:44 -0500 From: Phil Auld To: Peter Zijlstra Cc: tglx@linutronix.de, arnd@arndb.de, anna-maria@linutronix.de, frederic@kernel.org, luto@kernel.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, oliver.sang@intel.com Subject: Re: [PATCH v2 6/6] sched: Default enable HRTICK Message-ID: <20260121222444.GA1370038@pauld.westford.csb> References: <20260121162010.647043073@infradead.org> <20260121162508.119040984@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260121162508.119040984@infradead.org> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Hi Peter, On Wed, Jan 21, 2026 at 05:20:16PM +0100 Peter Zijlstra wrote: > ... for generic entry architectures. This decouples preemption from > CONFIG_HZ, leaving only the periodic load-balancer and various > accounting things relying on the tick. > > Signed-off-by: Peter Zijlstra (Intel) > --- > kernel/sched/features.h | 5 +++++ > 1 file changed, 5 insertions(+) > > --- a/kernel/sched/features.h > +++ b/kernel/sched/features.h > @@ -63,8 +63,13 @@ SCHED_FEAT(DELAY_ZERO, true) > */ > SCHED_FEAT(WAKEUP_PREEMPTION, true) > > +#ifdef TIF_HRTIMER_REARM > +SCHED_FEAT(HRTICK, true) > +SCHED_FEAT(HRTICK_DL, true) > +#else > SCHED_FEAT(HRTICK, false) > SCHED_FEAT(HRTICK_DL, false) > +#endif I maybe be missing something. But the title of this patch and the above code do not seem to match. Cheers, Phil > > /* > * Decrement CPU capacity based on time not spent running tasks > > > --