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 B470947F4A for ; Mon, 23 Sep 2024 16:00:30 +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=1727107232; cv=none; b=sOXKEvz4+mPDzwkQqC/8b0edKLZKqOa9tiEuUWtmzwW2q/tBv0klBnko+4TJt0aZ2Kh81Jh1l3U7ftZWCSyln2m2Wx15QBnGVAJWaJ8xCzm9OQgSM1W5zJaDeKkIdmWJWM1bOGB3/Gcm5uxbxZp+w6M+x2LYvSfYiL8OiA9rbE0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727107232; c=relaxed/simple; bh=HnnZXl6t2SP9KFfGoCRAgd1V5dELYV1Xc0nr7ISnYko=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tA6151YeaVL9KPmJUVttUSAcyHcGmW1sOP7hC2f84yEYgQlEHF30IChOtNC0ZFg8EyROJiCcY70ZVafGPBzj/0Ub40j7gUaGFVBqyUlDlkK7gVCTG2SfOpWBbRj/CTLTLlcMawu2G38j1AoWvKx9c4qhMhM8ImA/v0JmemZIqRs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=KBKdHHeX; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="KBKdHHeX" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727107229; 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=cxg5RZKuwS9yIPxC79el7eGj1kEOjwEq2LIarjz7NnI=; b=KBKdHHeXCIYswiu92G2T6aWtsVdxtxtk5vHTsU37OyT20+HYoG7eaIBUvvCHJsu1bWbYiE TqzBanLLJ+6HMEEzYBLoUKMgiEqnL50eD8GzQXxIbfivizhb7+qky9vAYbn0HEOvrI2q8H inFmrYCZ3CU0R0+l3oPp7MM3RODRKXw= 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-607-RiOgxZ2KOO-S_GrVQacELg-1; Mon, 23 Sep 2024 12:00:28 -0400 X-MC-Unique: RiOgxZ2KOO-S_GrVQacELg-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.40]) (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 8FC9E195FE2E; Mon, 23 Sep 2024 16:00:26 +0000 (UTC) Received: from pauld.westford.csb (unknown [10.22.32.189]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 292311922ACC; Mon, 23 Sep 2024 16:00:10 +0000 (UTC) Date: Mon, 23 Sep 2024 12:00:07 -0400 From: Phil Auld To: Tejun Heo Cc: andrea.righi@linux.dev, David Vernet , Giovanni Gherdovich , Kleber Sacilotto de Souza , Marcelo Henrique Cerri , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched_ext: Provide a sysfs enable_seq counter Message-ID: <20240923160007.GA313849@pauld.westford.csb> References: <20240921193921.75594-1-andrea.righi@linux.dev> <20240923104548.GA308802@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 3.0 on 10.30.177.40 On Mon, Sep 23, 2024 at 05:32:15AM -1000 Tejun Heo wrote: > Hello, > > On Mon, Sep 23, 2024 at 12:45:48PM +0200, Phil Auld wrote: > ... > > It's not a per scheduler counter, though. It's global. We want to know > > Yeah, the sequence is global but we can report the sequence at which a given > scheduler is loaded on each scheduler. That way, e.g., you can tell whether > a particular scheduler instance is the same one you looked at the last time > too. > > > that a (any) scx scheduler has been loaded at some time in the past. It's > > really only interesting when 0 or > 0. The actual non-zero number and which > > scheduler(s) don't matter that much. > > Not necessarily. e.g. You can also detect scheduler failing or being updated > for other reasons. Sure, but the primary purpose is practically boolean. > > > And it needs to persist when the scheduler is unloaded (I didn't look but > > I uspect the per scheduler attrs come and go?). > > Yes, the load sequence number should stay persistent across all schedulers, > but each scheduler should report the sequence number at which *it* was > loaded. Note that this doesn't really change anything now. If you only care > whether any SCX scheduler has ever been loaded, you'd always look under > root. > In my testing root is not there is nothing is loaded. Cheers, Phil > Thanks. > > -- > tejun > --