From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 AA05D3FF892 for ; Wed, 13 May 2026 11:53:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778673201; cv=none; b=cZbe3WRfQDNmFWrFgWlm+WRQHGbMUwM0Lg0b8J0NsjOyATMtGkucMaXn+eVIdy/S5Fa9ULkiF0bOdh3UeZhlnjPaDRisKJVPnKrB4J33hYXhGKT0F+2qUNavYamIqLDSTUUNIqwOco5uayuJBVoDf+HMTVrB5bjL0VbYHhe9n4o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778673201; c=relaxed/simple; bh=Dbh3tQlli5TwjK3LnbRRlkUL9NobZv5GAsmoBELXFOI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B1vWSfEQs6elLuqMJup1Z+E2B3ENNHxbmk07cBtXkoYiwh6hGSow13jKStFW0wbuhdqQB1x6506Q8fCpYdZhzk5QvN21174YGTYK4OZdsSIZ6ZoRNV0WSbHhvXbJI0wEdV5bxnZy+djn5uU/8HJnKoZdY89ublre/8naeCVybmE= 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=QZCwrngZ; arc=none smtp.client-ip=170.10.129.124 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="QZCwrngZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1778673198; 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=ikmgUVMt0O7lGh60KF0MLMZ4VkBEzta/remuC3+TkXo=; b=QZCwrngZgOlYCAJ3M4OnNM1PFYP3+YWM4b6611dm2JTxgNhHQaWoONiG0pNeXLhUa3Ofyu cwh7UAbBdX/1sFpgOiCmQrDVHKY396PyQHxJEuPyOY/eGFdaDeww0DvnYGSd3iSHYQ+uuy 5VSucRw963xi9UL1C/1+iJ0N1pAsjpc= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-533-IHVkPlywPFWOuo-ihtmgJg-1; Wed, 13 May 2026 07:53:14 -0400 X-MC-Unique: IHVkPlywPFWOuo-ihtmgJg-1 X-Mimecast-MFC-AGG-ID: IHVkPlywPFWOuo-ihtmgJg_1778673192 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 39D3918002C8; Wed, 13 May 2026 11:53:12 +0000 (UTC) Received: from pauld.westford.csb (headnet01.pony-001.prod.iad2.dc.redhat.com [10.2.32.101]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1DF781800576; Wed, 13 May 2026 11:53:07 +0000 (UTC) Date: Wed, 13 May 2026 07:53:05 -0400 From: Phil Auld To: Shrikanth Hegde Cc: mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, kprateek.nayak@amd.com, juri.lelli@redhat.com, vschneid@redhat.com, dietmar.eggemann@arm.com, tj@kernel.org, rostedt@goodmis.org, mgorman@suse.de, bsegall@google.com, arighi@nvidia.com Subject: Re: [PATCH v2 3/3] sched/fair: Add compile time check in fastpaths for CONFIG_SCHED_SMT=n Message-ID: <20260513115305.GA239187@pauld.westford.csb> References: <20260512152125.308280-1-sshegde@linux.ibm.com> <20260512152125.308280-4-sshegde@linux.ibm.com> <20260512165927.GD140541@pauld.westford.csb> 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: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On Wed, May 13, 2026 at 09:45:53AM +0530 Shrikanth Hegde wrote: > Hi Phil. > > On 5/12/26 10:29 PM, Phil Auld wrote: > > Hi Shrikanth, > > > > On Tue, May 12, 2026 at 08:51:25PM +0530 Shrikanth Hegde wrote: > > > For fastpaths such as wakeup, load balance even a minimal code additons > > > can pop up. Add IS_ENABLED checks there to ensure there is no overhead. > > > > "For fastpaths such as wakeup and load balance, even minimal code additions > > can add up. Add IS_ENABLED() checks..." ? > > > > Ok. > > > > > > > Other places are either have sched_smt_active() check or they are not in > > > > s/are// > > ok. > > > > > "have a sched_smt_active_check()" or drop "check" ? > > > > > > I was saying sched_smt_active() runtime gating is there for many fast paths where > cpu_smt_mask is being referred or those code paths are not fast paths. > > Let me re-word a bit. > I know what you were saying. I just wanted an article when I read it :) Cheers, Phil > > Otherwise lgtm. > > > > Reviewed-by: Phil Auld > > > > > > Cheers, > > Phil > > > Thanks for the review. > --