From patchwork Tue Apr 26 08:21:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 566722 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 8D830C433F5 for ; Tue, 26 Apr 2022 08:27:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238819AbiDZIaF (ORCPT ); Tue, 26 Apr 2022 04:30:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239180AbiDZI3Q (ORCPT ); Tue, 26 Apr 2022 04:29:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF28E3AA48; Tue, 26 Apr 2022 01:24:41 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 25BDC61776; Tue, 26 Apr 2022 08:24:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1623DC385A0; Tue, 26 Apr 2022 08:24:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650961480; bh=XOebLSvaZWmiWP1AJ5v3UtPKfIYko/HEBYFcseh+p9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nzjeMiS4RBdYbyc1jhd/gzntPA60UdxwG3xOf1Hr+TozYHoHvrfh3xta7JZpjOMpb xLTVNTS7AhA7GXsU5e7zNzR2I9oG65GiWUQ9xoXXeVQt7xL3GnyzwHn6nXOuA59j21 SC9kmquE2qq6sOFy5ZQypfaFzKkTeiLcXY60QAWA= 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 4.14 24/43] powerpc/perf: Fix power9 event alternatives Date: Tue, 26 Apr 2022 10:21:06 +0200 Message-Id: <20220426081735.231873391@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081734.509314186@linuxfoundation.org> References: <20220426081734.509314186@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 efb19b089023..75d3a10e20fe 100644 --- a/arch/powerpc/perf/power9-pmu.c +++ b/arch/powerpc/perf/power9-pmu.c @@ -107,11 +107,11 @@ extern struct attribute_group isa207_pmu_format_group; /* 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[])