From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 95D3B4EB45; Mon, 1 Jul 2024 12:31:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719837112; cv=none; b=F1opFW5hb229mD9tWK8YUOnogcVtv3rsDlEbIpV3rckEdL7JKAXGJDVlhJlieqxRiih2VWhG+g8PgLk2o7KYpz1jytbMo4eYoQo1vMVNtbSaPW86JBv0IJlgMPeDb8mEtabUOir+QikdcjM/nOQOdVZ8bIpID7ZvJoNWIQvGVxU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719837112; c=relaxed/simple; bh=BReYYFfhYkxLFM4o8fNg1xwFvXPIu8yp6wM+BNmK3+w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oxNLgo+7HNeeVHrHtrwZ39gd+JtmBHON+P58MQfB9o8JjGZtHoYYlygQBbxslTV6nofkcOv7Stp49NmSMNKQXMR2uZWG88Vy1aAg+ahCvhl+eWDidKKlgAQaB2sAy4AKJHrpJEHZNOqqmCAuDISqkup/IaK0xu+7o4W744ufzjY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=SpIE163G; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="SpIE163G" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=GXpf8n1yqAvgwJA1SS73M21QSVJ7nOMPXPy5McCX+TE=; b=SpIE163GOjkK5rTuYIch0NzY6L s/l2M7/AexFDUy1Pg/kieJc91aLKJSup/P3bqpGDF+76kjacLyPOu5n3kDQZhJ57G4bhEpG4fgkeC YvYfXu2VOt3wlfkM8YvGJVaX5n0whHFWU7DMQUmOiRcq6BR4dLqHR7i39mVyR3Zh3t/ilO+c5UcIL qkt8PRTnWvFwWAyFo9bwO+UcJFPK/geVL9OAkE4Mm8ER0Lt74G6pd6sn04I4ylGmFFLa2+J0anG9m d2z3P+La7ENDGlRtJH/Rh1U04CUPBQ279AUXIE+KBWDh4uq9FgIWW8CXkysSvNAA6238xIGEd62Z+ WD5FEKYg==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.97.1 #2 (Red Hat Linux)) id 1sOGC4-00000009edw-1ZtJ; Mon, 01 Jul 2024 12:31:41 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 781BF300694; Mon, 1 Jul 2024 14:31:37 +0200 (CEST) Date: Mon, 1 Jul 2024 14:31:37 +0200 From: Peter Zijlstra To: Sebastian Andrzej Siewior Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Daniel Bristot de Oliveira , Frederic Weisbecker , Ian Rogers , Ingo Molnar , Jiri Olsa , Kan Liang , Marco Elver , Mark Rutland , Namhyung Kim , Thomas Gleixner Subject: Re: [PATCH v4 3/6] perf: Shrink the size of the recursion counter. Message-ID: <20240701123137.GF20127@noisy.programming.kicks-ass.net> References: <20240624152732.1231678-1-bigeasy@linutronix.de> <20240624152732.1231678-4-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-perf-users@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: <20240624152732.1231678-4-bigeasy@linutronix.de> On Mon, Jun 24, 2024 at 05:15:16PM +0200, Sebastian Andrzej Siewior wrote: > There are four recursion counter, one for each context. The type of the > counter is `int' but the counter is used as `bool' since it is only > incremented if zero. > > Reduce the type of the recursion counter to an unsigned char, keep the > increment/ decrement operation. Does this actually matter? Aren't u8 memops encoded by longer instructions etc..