From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) (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 EEFD7225408; Fri, 9 Jan 2026 16:14:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767975286; cv=none; b=rpFOEXwXl1Et3TeGjGSxz3FMnjL5kVeVaR+7mbrgYy2B3jvgokFUM2Cox5wyWwpqhHwcsa97jkiSFoW92K5C7+TXr8SeV/nZrqoLADMrzC53djZ6dESqGZ3u2hcEgEy+tQDX8Tk4WS/yM9KLkSlzWCzMa25ubtmguzEEPsQPeRk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767975286; c=relaxed/simple; bh=OWC1ntZBQKWTkIZk633veMv1AKus1gRIEYKhERIX7BA=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tWpauoXs3DlgULeBNMEqKC6Newh2DVtQ3RpSPvbU/qfFg4K40qAd6nVShV+68s+BN7fd1G8qZVowtQB49ezmXsgzWRN9dAhhzZOSGAIdwJF8FkQRgSLj1sYPUrO3aysVL0r9+bV90PGimXNKdevnSZRZQJ5W4Koy9bXTtpOOP7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 8CCA61A0325; Fri, 9 Jan 2026 16:14:37 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf14.hostedemail.com (Postfix) with ESMTPA id 77B3730; Fri, 9 Jan 2026 16:14:35 +0000 (UTC) Date: Fri, 9 Jan 2026 11:15:06 -0500 From: Steven Rostedt To: Petr Tesarik Cc: Masami Hiramatsu , Mathieu Desnoyers , Sebastian Andrzej Siewior , Clark Williams , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH] ring-buffer: Use a housekeeping CPU to wake up waiters Message-ID: <20260109111506.66ad545a@gandalf.local.home> In-Reply-To: <20260109095756.13deb429@mordecai> References: <20260106091039.2012108-1-ptesarik@suse.com> <20260106170405.425f469e@gandalf.local.home> <20260107085009.58fcffd4@mordecai> <20260107105137.4cf9a67e@mordecai> <20260107111709.0d115cd8@gandalf.local.home> <20260107111935.3befc296@gandalf.local.home> <20260108093932.252f6bc7@mordecai> <20260108115800.7a7fc8a7@gandalf.local.home> <20260109095756.13deb429@mordecai> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: ihb8rxsfsw8zrdo3szasojjm3ouwg3zs X-Rspamd-Server: rspamout02 X-Rspamd-Queue-Id: 77B3730 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+oky8s4MPjftNUIdm5FDOaAGDH+y5fxEA= X-HE-Tag: 1767975275-701826 X-HE-Meta: U2FsdGVkX19shqUHAwfxAoXdYF4FPvcwR/jQmaYQwN2e1O6cR4XGs/kBLqxWcBQDErfEO2PCfRGVEMCv+MuQz/T1PTHAWDFTEK4tKq+KpqLUDPtVsyPPBCynXC3nOGDTpLBqcaJRw1phM2Rd0l7MW0S8UYxv1mRA+VOifB4Kw07DJssOj5YUDQOPYlsJhR3mev3uce6rLBKzjzTXnYz071S9YpkYTUt9ZaPUvZ7AYC2eaBtm4q+OcZQnLjIeM8oHqK0VQv3vCqr8vKAg95uZQm3V9P7vkDUR/MajcHlHaMZ7hWj1XntnsmW5XD9dF7dkomoUZXs5Hak9z37u0giCxYbZ51k5mXYIMUusxjcuOQpteWDA2i0vAT2iOkUYGYio On Fri, 9 Jan 2026 09:57:56 +0100 Petr Tesarik wrote: > I have removed both "inline" and "noinline" in v2, leaving it at the > discretion of the compiler. If you believe it deserves a "noinline", > feel free to add it. FWIW on x86-64, I didn't observe any measurable > diference either in latency or instruction cache footprint. Please add the noinline. I went through and added strategic "noinline" and "__always_inline", as well as placing "likely()" and "unlikely()" and dropped the cost of adding an event from just under 300ns down to less than 150ns. This code is called during function tracing (hit at every function call), and yes, every little bit helps! -- Steve