From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=193.142.43.55 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794581790; b=t7e8ZATj135yn2pyKAt9dFD9eV2pviWcELZC9mdfmAse44G8UEVb+Fj+cGzPqGIyziiD 8JwxIzv84DIG1skv9SyIRvWBfV53zhs5pc6SlzG7hy/AT5/+c/AaPxR9ORq5HUihnApcl N0OCCjSTR1xGI9sg4ja4VXckpoUervuPqUrisnYNhe0DdkPZqbzuI6xwmeRx5wUBKrNij pIiyqmlu9UmmEGoK+5v9TwN82+uzch0wz2Tf32dX8shxoPyajlkQQkoRHPzzIX76zVR8g ICyB7QeQReF0e7PXLzUxS3WxUL9mpUnQQmm+C1a8Py1UpVVMHPYSNpQ5ZKOJ1jNNrqQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794581790; h=DMARC-Filter:From:DKIM-Signature:DKIM-Signature:To:Cc:Subject: In-Reply-To:References:Date:Message-ID:MIME-Version:Content-Type; bh=djMQ9Rq5O2IwlxIxPHVCe+0cQ6bgchm1ltqKDGJGPWA=; b=oXbJzCZKJx9m0mfsuv+Qp3/QfzjYu56IMCEQiqHKAgKvwlTjNYUaY2WncKAooVKk0Nfy 0jhoAISr5T41qBxVumqsDSfjK82y4od1qANgYJG9P2Yf9hGrRsQqsPAz0Ca85fmWfkoAE DoOYb2Tv8rNmDBvbSO4NYqYHFcBdVXJp3wmUE/UC50qUzwCInJE8qEnVCf7uGBoPaUyHL OMN30EoZoBuD+50RRFzcglYWRG0cI5RUswpJigLrV2Wnb3vpV6K/13heX+vRy2cgPsz0m yAvGiDRuZ0grDBscp3KNW9mCHyFGM5M+27vRxq9wJ5gCLTH8QH/Z2wAtKXtdrXUXQuQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=OfSh6y5X; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=VPzeeLFP; arc=none smtp.remote-ip=193.142.43.55 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 32449606A32D for ; Fri, 13 Nov 2026 14:56:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 32449606A32D Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.a=rsa-sha256 header.s=2020 header.b=OfSh6y5X; dkim=pass header.d=linutronix.de header.i=@linutronix.de header.a=ed25519-sha256 header.s=2020e header.b=VPzeeLFP From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1794581787; 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=djMQ9Rq5O2IwlxIxPHVCe+0cQ6bgchm1ltqKDGJGPWA=; b=OfSh6y5XzvXKLPTJeaMP0FyKaS9E2vtYZLt5MnIeAbTMsmKCdFh9DS2BTPZyU9Kz06yJd0 Bs1b1wNcHTOI8vys+pfMetmYmvw0GtivY/t+ddUW9TeFmNRceYfuGURlxwH9twefBrMN/7 UzcihZ3IRhWVXK7/auuXatE0LIQ1WTuDqeQhx3ZOmo76hXxZ+/clN+4OzOmCJuIKGF1wwp c7miIvWZ0oBqfN1GbF7/0JCbl1I+DOOStKblQj67SnpIC7bPicidI0lOmrPTmAxkio+E/R 38HczTTa4FZF6woRp4qnQ2jzLgFIY4tCHXtdbQXnudWgA2idin4UxZxypXGf+g== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1794581787; 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=djMQ9Rq5O2IwlxIxPHVCe+0cQ6bgchm1ltqKDGJGPWA=; b=VPzeeLFP7y6FGPj3vf4/kARuHJXyXcVpgKHn09dDFHlkCQ16d8vPzQhLvMLIxPHQNWb4SC VrinhYJOuW94bKAQ== To: Daniel Wagner , Steven Rostedt , Tomas Glozar , Sebastian Andrzej Siewior , Clark Williams Cc: linux-trace-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Daniel Wagner Subject: Re: [PATCH v2] rtla/timerlat: Lock the memory of the user-space threads In-Reply-To: <20261113-rtla-mlock-v2-1-14382f140da0@monom.org> References: <20261113-rtla-mlock-v2-1-14382f140da0@monom.org> Date: Fri, 13 Nov 2026 16:02:26 +0106 Message-ID: <87o6bswzj9.fsf@jogness.linutronix.de> X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain Hi Daniel, On 2026-11-13, Daniel Wagner wrote: > diff --git a/tools/tracing/rtla/src/timerlat_u.c b/tools/tracing/rtla/src/timerlat_u.c > index c80edaf07b00..5e7a23fb9fc3 100644 > --- a/tools/tracing/rtla/src/timerlat_u.c > +++ b/tools/tracing/rtla/src/timerlat_u.c > @@ -37,6 +38,13 @@ static int timerlat_u_main(int cpu, struct timerlat_u_params *params) > cpu_set_t set; > int retval; > > + /* > + * Fault in and lock all memory before switching to a real-time > + * priority, so that page faults don't show up as latency. > + */ It isn't because the page faults show up as latencies. It is because doing non-real-time work with a real-time priority is stealing the CPU away from other real-time tasks that presumably have actual real-time work to do. This program peforms severeal non-real-time activities with the real-time priority, which is not setting a good example. But I am only reviewing your patch, not the full source. John