From patchwork Tue Apr 26 08:21:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 566499 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01D6BC43219 for ; Tue, 26 Apr 2022 09:08:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346643AbiDZJIu (ORCPT ); Tue, 26 Apr 2022 05:08:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347929AbiDZJGX (ORCPT ); Tue, 26 Apr 2022 05:06:23 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3989AB8985; Tue, 26 Apr 2022 01:47:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F1CDCB81A2F; Tue, 26 Apr 2022 08:47:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FD97C385A0; Tue, 26 Apr 2022 08:47:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962845; bh=euVy0+SWJLyLoXQycColti30EIyblijkVeISgJbnouw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x7w6TOSmBg+c4Rf+WNxsVmeoFLmHkZTBsckfamgxgJEPE9yL+DXZNi651wRt+j6js 1exWUUrdZTKhTEu/5YLVozu7077CgMGpunhxEqvJ78fbALmbvMYhij9XPpxQFNZrSo EI5VFgVMfx6A1PikAmLJw3sgVXzZTuO1AM8sT7uE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Athira Rajeev , Madhavan Srinivasan , Michael Ellerman , Sasha Levin Subject: [PATCH 5.17 109/146] powerpc/perf: Fix power9 event alternatives Date: Tue, 26 Apr 2022 10:21:44 +0200 Message-Id: <20220426081753.120091480@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081750.051179617@linuxfoundation.org> References: <20220426081750.051179617@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Athira Rajeev [ Upstream commit 0dcad700bb2776e3886fe0a645a4bf13b1e747cd ] When scheduling a group of events, there are constraint checks done to make sure all events can go in a group. Example, one of the criteria is that events in a group cannot use the same PMC. But platform specific PMU supports alternative event for some of the event codes. During perf_event_open(), if any event group doesn't match constraint check criteria, further lookup is done to find alternative event. By current design, the array of alternatives events in PMU code is expected to be sorted by column 0. This is because in find_alternative() the return criteria is based on event code comparison. ie. "event < ev_alt[i][0])". This optimisation is there since find_alternative() can be called multiple times. In power9 PMU code, the alternative event array is not sorted properly and hence there is breakage in finding alternative events. To work with existing logic, fix the alternative event array to be sorted by column 0 for power9-pmu.c Results: With alternative events, multiplexing can be avoided. That is, for example, in power9 PM_LD_MISS_L1 (0x3e054) has alternative event, PM_LD_MISS_L1_ALT (0x400f0). This is an identical event which can be programmed in a different PMC. Before: # perf stat -e r3e054,r300fc Performance counter stats for 'system wide': 1057860 r3e054 (50.21%) 379 r300fc (49.79%) 0.944329741 seconds time elapsed Since both the events are using PMC3 in this case, they are multiplexed here. After: # perf stat -e r3e054,r300fc Performance counter stats for 'system wide': 1006948 r3e054 182 r300fc Fixes: 91e0bd1e6251 ("powerpc/perf: Add PM_LD_MISS_L1 and PM_BR_2PATH to power9 event list") Signed-off-by: Athira Rajeev Reviewed-by: Madhavan Srinivasan Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220419114828.89843-1-atrajeev@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/power9-pmu.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/perf/power9-pmu.c b/arch/powerpc/perf/power9-pmu.c index 4b7c17e36100..37b2860db483 100644 --- a/arch/powerpc/perf/power9-pmu.c +++ b/arch/powerpc/perf/power9-pmu.c @@ -133,11 +133,11 @@ int p9_dd22_bl_ev[] = { /* Table of alternatives, sorted by column 0 */ static const unsigned int power9_event_alternatives[][MAX_ALT] = { - { PM_INST_DISP, PM_INST_DISP_ALT }, - { PM_RUN_CYC_ALT, PM_RUN_CYC }, - { PM_RUN_INST_CMPL_ALT, PM_RUN_INST_CMPL }, - { PM_LD_MISS_L1, PM_LD_MISS_L1_ALT }, { PM_BR_2PATH, PM_BR_2PATH_ALT }, + { PM_INST_DISP, PM_INST_DISP_ALT }, + { PM_RUN_CYC_ALT, PM_RUN_CYC }, + { PM_LD_MISS_L1, PM_LD_MISS_L1_ALT }, + { PM_RUN_INST_CMPL_ALT, PM_RUN_INST_CMPL }, }; static int power9_get_alternatives(u64 event, unsigned int flags, u64 alt[])