From nobody Tue Dec 30 09:16:34 2025 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 E8AC7C2BB3F for ; Sat, 18 Nov 2023 15:52:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231207AbjKRPwc (ORCPT ); Sat, 18 Nov 2023 10:52:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40610 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230241AbjKRPwR (ORCPT ); Sat, 18 Nov 2023 10:52:17 -0500 Received: from mail-yw1-x112f.google.com (mail-yw1-x112f.google.com [IPv6:2607:f8b0:4864:20::112f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F07410EC for ; Sat, 18 Nov 2023 07:51:24 -0800 (PST) Received: by mail-yw1-x112f.google.com with SMTP id 00721157ae682-5bf58914bacso32809437b3.3 for ; Sat, 18 Nov 2023 07:51:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1700322682; x=1700927482; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=9UsBR6w3W758FRiCdHZSwpEWSnagR0QzKE5nlW0aMIc=; b=nQs2UW3wVet4kSsKbSzaXKJxEP2BuksvcT/EJAsDwDfEp6x0P9IKYl818BEEF4AWP5 HGtA5IY818T7+BWc3POZXJRStncOM+cEpVsgppyURmDZPKkHamsdXZTwgwWI4kLk+au4 epfgzV4FElITDS9w4wHt4jRqEuiufR4mHUAgAx95EYNuBk8qBK/ozLdmZEIPThfhhSi2 nfRFUF/4bRkUEYrp1Qx9A9GAVRaAZb7JK0tdeX1K5a63pfMrnpWUmd6q1kdL/wBa+LGE 0IsXZQl4aE+RMaJOPZ1DRx6w0VbY4c2db9ZAB3Q2TTwTvx9iJ9nE93Bf0z1YbB4K8Op6 JJOQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700322682; x=1700927482; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9UsBR6w3W758FRiCdHZSwpEWSnagR0QzKE5nlW0aMIc=; b=ghirHcFsp0Z5YM/lQMSVuwGaysjCiq3GZC0nFrWUKgyCjdDJ9h7+H4GNRVt+QQS+DB r7caDzVSwXRCbSgITNvvqhDKS0T18RI6ciunWBUe1gGPc1q4GY8pS3Dtqmo++gLlZchu 1/DoIxHumrmChxJK7WkD0qDnLPE+PK8Wu2Up94aGpGa9mLBWzOtjVEpA+QQ882BjKd/o qE7P6yq3wirdlsB929LsVpXpovpIrQj2k/qP6r3Tyffi/21dYpE8brSrKbqgcpLaEocg tlVUcX3QzJEbZVX0y55OQEeIEyILd3i68jGzrVjIDVzgzRyQ+6tVmrDEoNAMnn/ypG4m dCIQ== X-Gm-Message-State: AOJu0YwD2iYuveaU0a+UiAU13EZWIVfbcOfWx4tLejy63EiPQzSRZTzR fQjL5n114NS7OI3jMZvgHUC+lNZk0diFg21W X-Google-Smtp-Source: AGHT+IFMi3zL8WSF03nEf+gU11A9ztIok6tcrLg24vsR46a+e0EFl+1hnebBli0fdxvl68Hs4Jerug== X-Received: by 2002:a0d:dc43:0:b0:59b:ec85:54ee with SMTP id f64-20020a0ddc43000000b0059bec8554eemr3160808ywe.39.1700322682161; Sat, 18 Nov 2023 07:51:22 -0800 (PST) Received: from localhost ([2601:344:8301:57f0:48a9:bd4c:868d:dc97]) by smtp.gmail.com with ESMTPSA id d19-20020a814f13000000b0058ddb62f99bsm1187785ywb.38.2023.11.18.07.51.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Nov 2023 07:51:21 -0800 (PST) From: Yury Norov To: linux-kernel@vger.kernel.org, Shuai Xue , Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org Cc: Yury Norov , Jan Kara , Mirsad Todorovac , Matthew Wilcox , Rasmus Villemoes , Andy Shevchenko , Maxim Kuvyrkov , Alexey Klimov Subject: [PATCH 08/34] drivers/perf: optimize ali_drw_get_counter_idx() by using find_bit() Date: Sat, 18 Nov 2023 07:50:39 -0800 Message-Id: <20231118155105.25678-9-yury.norov@gmail.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20231118155105.25678-1-yury.norov@gmail.com> References: <20231118155105.25678-1-yury.norov@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The function searches used_mask for a set bit in a for-loop bit by bit. We can do it faster by using atomic find_and_set_bit(). Signed-off-by: Yury Norov Acked-by: Will Deacon --- drivers/perf/alibaba_uncore_drw_pmu.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/drivers/perf/alibaba_uncore_drw_pmu.c b/drivers/perf/alibaba_u= ncore_drw_pmu.c index 19d459a36be5..2a3b7701d568 100644 --- a/drivers/perf/alibaba_uncore_drw_pmu.c +++ b/drivers/perf/alibaba_uncore_drw_pmu.c @@ -274,15 +274,9 @@ static const struct attribute_group *ali_drw_pmu_attr_= groups[] =3D { static int ali_drw_get_counter_idx(struct perf_event *event) { struct ali_drw_pmu *drw_pmu =3D to_ali_drw_pmu(event->pmu); - int idx; + int idx =3D find_and_set_bit(drw_pmu->used_mask, ALI_DRW_PMU_COMMON_MAX_C= OUNTERS); =20 - for (idx =3D 0; idx < ALI_DRW_PMU_COMMON_MAX_COUNTERS; ++idx) { - if (!test_and_set_bit(idx, drw_pmu->used_mask)) - return idx; - } - - /* The counters are all in use. */ - return -EBUSY; + return idx < ALI_DRW_PMU_COMMON_MAX_COUNTERS ? idx : -EBUSY; } =20 static u64 ali_drw_pmu_read_counter(struct perf_event *event) --=20 2.39.2