From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BB6512D9ED1 for ; Sat, 6 Dec 2025 10:12:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765015945; cv=none; b=r4xmJTmTd1FWfgk4uCeAEuaD4uxe16xY9WZHe8cAai0sm0yGeAEopfckUwSYZtHg6Xn5GAcHSTme5A7cvSu0yP4Gs26bXrMAbt5fuP13GZoswedE6hFy7xF/+DJxiYocLWRAvVrgym6X4L5Zb8HakNP8RrU2+1jo+2W2H96iT0M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765015945; c=relaxed/simple; bh=gEPPYhHvr9A+R1IFKmY4xHSSA0MRAHTeB6bPiHpkDqQ=; h=Date:Message-ID:From:To:Cc:Subject:MIME-Version:Content-Type; b=H5bat5w35byB2gfCnw9VCEb0hWvMkzkWD9Ihll9Yx0+IottQjBKLw4/lWVEuUPy0LqkZWah6nUDVZfJV+SzusjcmVuuH41fpAUHLXxoIrf0iZ7Tq7eiEEwwEITkKF2+pLcx6hG7TIjWb32mVLu5wTRbB7Z+CIc50CBYWU/uzpFo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=B5EmFgy2; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="B5EmFgy2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BDE9C4CEF5; Sat, 6 Dec 2025 10:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765015945; bh=gEPPYhHvr9A+R1IFKmY4xHSSA0MRAHTeB6bPiHpkDqQ=; h=Date:From:To:Cc:Subject:From; b=B5EmFgy2hURoQzerjGOQBfs3JKXTQAzBwcgv6onh5pvPGrm1kyk1ZfWwnrg2gi2kB VpgilA/xKxODB3dhhFrQJBR4O9+nfIhVcFJWa2Z2wxcjAX1AmJknqQLuYO290hPFu6 bsJrZt81e5cGpXC6060gDEQeBl0h/DLcF9uvikhJpAMZdcFUnA96YLMnpMWkvdy1cC YFqycqAfW/hVSsGxRMukAjlr/b38EtPUXDF672qRnnmiA2QFz0lVKHlSVbeUHx1cRk tIfBAHDDartI8eAO2vyg641Byfo3EsHqMb0wTpUkEznPVPhmqHnk6Uw6/djnGK3dE1 sqSPG8PYMJzdA== Received: from sofa.misterjones.org ([185.219.108.64] helo=lobster-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vRpH5-0000000AwIW-0I5X; Sat, 06 Dec 2025 10:12:23 +0000 Date: Sat, 06 Dec 2025 10:12:22 +0000 Message-ID: <87zf7vex6h.wl-maz@kernel.org> From: Marc Zyngier To: Daniel Lezcano , Thomas Gleixner Cc: Linux Kernel Mailing List Subject: Fate of CONFIG_IRQ_TIMINGS and co User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: daniel.lezcano@linaro.org, tglx@linutronix.de, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Hi both, While fixing some ancient MIPS crap, I noticed that the IRQF_TIMER flag wasn't being provided to any clockevent driver that uses percpu interrupts, starting with the ARM architected timer. Thinking that I might as well be fixing that, I started to dig into it, only to realise that it is simply impossible to enable the IRQ timing subsystem (CONFIG_IRQ_TIMINGS isn't selectable by a luser, and TEST_IRQ_TIMINGS depends on it...). Even if I manually hack the Kconfig to compile the timing infrastructure and allow the selftest to be selected, nothing really makes use of this, as the static key that controls the accounting is never flipped. The selftest itself only cares about the accounting data structure, and not interrupts. This appears to be dead code, and seems to have been so for the past 6 years. The obvious question is therefore: why do we have it the first place? It isn't finished, not plugged in, and if it was, would fail to correctly account for exactly 100% of the timer interrupts on the systems I care about. If this is a work in progress and that there is a line of sight to having it working upstream, that's great, and I will happily post the few fixes I have for it. Otherwise, can we do ourselves a favour and consider dropping it? Thanks, M. -- Jazz isn't dead. It just smells funny.