From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04965C433DF for ; Mon, 8 Jun 2020 18:31:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC1352074B for ; Mon, 8 Jun 2020 18:31:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726205AbgFHSbg (ORCPT ); Mon, 8 Jun 2020 14:31:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:44424 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726098AbgFHSbg (ORCPT ); Mon, 8 Jun 2020 14:31:36 -0400 Received: from oasis.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E8428206D5; Mon, 8 Jun 2020 18:31:34 +0000 (UTC) Date: Mon, 8 Jun 2020 14:31:33 -0400 From: Steven Rostedt To: LKML Cc: Ingo Molnar , Andrew Morton , Mel Gorman Subject: [for-next][PATCH] tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option Message-ID: <20200608143133.0e72efde@oasis.local.home> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git for-next Head SHA1: 388d8bdb87e01bcea6d0b2bf797b5f6d7b2401fb Mel Gorman (1): tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option ---- kernel/trace/Kconfig | 9 --------- 1 file changed, 9 deletions(-) --------------------------- commit 388d8bdb87e01bcea6d0b2bf797b5f6d7b2401fb Author: Mel Gorman Date: Thu Apr 9 11:40:34 2020 +0100 tracing: Remove obsolete PREEMPTIRQ_EVENTS kconfig option The PREEMPTIRQ_EVENTS option is unused after commit c3bc8fd637a9 ("tracing: Centralize preemptirq tracepoints and unify their usage"). Remove it. Note that this option is hazardous as it stands. It enables TRACE_IRQFLAGS event on non-preempt configurations without the irqsoff tracer enabled. TRACE_IRQFLAGS as it stands incurs significant overhead on each IRQ entry/exit. This is because trace_hardirqs_[on|off] does all the per-cpu manipulations and NMI checks even if tracing is completely disabled for some insane reason. For example, netperf running UDP_STREAM on localhost incurs a 4-6% performance penalty without any tracing if IRQFLAGS is set. It can be put behind a static brach but even the function entry/exit costs a little bit. Link: https://lkml.kernel.org/r/20200409104034.GJ3818@techsingularity.net Signed-off-by: Mel Gorman Signed-off-by: Steven Rostedt (VMware) diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 75407d5dc83a..0c82ac2c5688 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -258,15 +258,6 @@ config TRACE_PREEMPT_TOGGLE Enables hooks which will be called when preemption is first disabled, and last enabled. -config PREEMPTIRQ_EVENTS - bool "Enable trace events for preempt and irq disable/enable" - select TRACE_IRQFLAGS - select TRACE_PREEMPT_TOGGLE if PREEMPTION - select GENERIC_TRACER - default n - help - Enable tracing of disable and enable events for preemption and irqs. - config IRQSOFF_TRACER bool "Interrupts-off Latency Tracer" default n