From patchwork Fri Nov 1 03:46:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Caleb Sander Mateos X-Patchwork-Id: 13858681 Received: from mail-io1-f100.google.com (mail-io1-f100.google.com [209.85.166.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0D48F13FD83 for ; Fri, 1 Nov 2024 03:48:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.100 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730432934; cv=none; b=C23iWv9aq3LmOyUcD+R/YTVHd9FPU3HelUVX/FTiNMbYHMeMrxrcY5QV6uXZO9iHnzpCKTgiAtlhNUIy2rtW6cmIt30qix+WZUQKUEIz+Duc4kXKa6WGELT/a4YnS4FCf7OAWRI0QL51kod8rNf9c0qvXa8mSdY1EyWf33LQaI8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730432934; c=relaxed/simple; bh=MZxHaEa7buDfvPC/4WE/aTVuUcf+xHReOo835eWZAUc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=PnFmt5b/C7S0cBZ3PhxZB/NOpz3DBn4qdAeyZLpr2morI815Iiu5tnPzN0Fts0aULt+1wX+T30f4J8YRspfE614Da5S1YXPMRa+kNF6MWWvdSrUl1YEoUmBc5W/RZs0llbVOXGihBW/IptW+DmaWDGmzp4TNpBelc3roMU29lBA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com; spf=fail smtp.mailfrom=purestorage.com; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b=HCs9zHau; arc=none smtp.client-ip=209.85.166.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=purestorage.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b="HCs9zHau" Received: by mail-io1-f100.google.com with SMTP id ca18e2360f4ac-83ab462ccb6so5622739f.1 for ; Thu, 31 Oct 2024 20:48:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=purestorage.com; s=google2022; t=1730432931; x=1731037731; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=iFtIYGNmdHvtGkRyGJ94EvP76ryCIg69gweJeFB48t0=; b=HCs9zHauggqjpYWcYjPW0xyxkRycf0hDSS39kyc0zHdFnydwppplgrE1wdeQ5NzVRe 2UL+kZaSW0UlRFBaozlQ9QGRevlzr+YOgQ51qygXXOakv7lC1ga+Bqga7JWwRXQY+643 AQq9+dpD8d0AyGWAWxH93XJYCQ8VQgEc3BTgmy3bKmdJKGgjOS8UGbC3L6nVO1B7dySE XHBr7ShVirOqWTMv8bzzHIXE7quxivyMA9NAmTszaZz4wKBGu+rkxI2atTOwnAbjh4yO TV1L0//awQova1WwEsJc0z6ZoIMswU1k1vHzkcfGP/PmP2lTcxWg+fiXfwoed5RjwdNY lR0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730432931; x=1731037731; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=iFtIYGNmdHvtGkRyGJ94EvP76ryCIg69gweJeFB48t0=; b=xPZuPFrH4XTBO7aBASTj2bTAz1PcUQHQpz6EtsGUIBfL51I7Q7OURctx3Dv3RghI22 Mv5SkWALLOf65tBj7AHaDRAAc0631YFYxy4yav/6+cS2hSMtDCBkitEX1i3b4OQOQTCN SJa3dSymCieZxtIKsNu2FwPK37xqRUQlSvfzRPfgHLsF/sjAQhas4hM6Z4laHxswsUNx NKWnpyE7ywF6PYJrxa7n06MX9W8lui8Dzo9HFElMyNXgxka3JnyX6brantzLGC2mHqOi lEWGoP+L6tAb/SLCRpl0ASto1I8WRRHW2cyU59cSSTjCdgFdkJ2djiDHxz59HXLxEbce tyKQ== X-Forwarded-Encrypted: i=1; AJvYcCXK2ew8NMm5OhqJ4N3rXCxc+jlzXRyHFluZq1z0xKNWm++Hkp0NYM8R/HRAkcsq+pHerqXATVhcj0q1@vger.kernel.org X-Gm-Message-State: AOJu0Yw9I68mQ/hvPrnBSD7b6M8rU61NjBs+kayXo5K6+dYhiWGSZ3CJ Dx4zB14saBUQcoRujSK8j0rY5JoybBO1g6pyFRe3sT7CJeQqRkOTFEiUVaNH99LQER2AqUu3ljB 5sZOl2rb7cZee8YFsDCIVKTAS6KP7M1J2paB2prR3KBZHc0lG X-Google-Smtp-Source: AGHT+IGeAIngWc5LMAF4LFYsaT5zMsZvEQP0mtRiGlcTjVrfrCa0VFOydr5yNiWCR5zgfn9ud1jX8qtLZ/w6 X-Received: by 2002:a6b:d90c:0:b0:82a:a4f0:c95e with SMTP id ca18e2360f4ac-83b1c60c9e0mr536930939f.5.1730432931086; Thu, 31 Oct 2024 20:48:51 -0700 (PDT) Received: from c7-smtp-2023.dev.purestorage.com ([2620:125:9017:12:36:3:5:0]) by smtp-relay.gmail.com with ESMTPS id ca18e2360f4ac-83b67cde42esm10054639f.35.2024.10.31.20.48.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Oct 2024 20:48:51 -0700 (PDT) X-Relaying-Domain: purestorage.com Received: from dev-csander.dev.purestorage.com (dev-csander.dev.purestorage.com [10.7.70.37]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id D22243406A8; Thu, 31 Oct 2024 21:48:49 -0600 (MDT) Received: by dev-csander.dev.purestorage.com (Postfix, from userid 1557716354) id BD92DE41EB6; Thu, 31 Oct 2024 21:48:19 -0600 (MDT) From: Caleb Sander Mateos To: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Caleb Sander Mateos , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next 1/2] mlx5/core: avoid memory barrier in eq_update_ci() Date: Thu, 31 Oct 2024 21:46:39 -0600 Message-ID: <20241101034647.51590-1-csander@purestorage.com> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The memory barrier in eq_update_ci() after the doorbell write is a significant hot spot in mlx5_eq_comp_int(). Under heavy TCP load, we see 3% of CPU time spent on the mfence. As explained in [1], this barrier is only needed to preserve the ordering of writes to the doorbell register. Use writel() instead of __raw_writel() for the doorbell write to provide this ordering without the need for a full memory barrier. memory-barriers.txt guarantees MMIO writes using writel() appear to the device in the same order they were made. On strongly-ordered architectures like x86, writel() adds no overhead to __raw_writel(); both translate into a single store instruction. Removing the mb() avoids the costly mfence instruction. [1]: https://lore.kernel.org/netdev/CALzJLG8af0SMfA1C8U8r_Fddb_ZQhvEZd6=2a97dOoBcgLA0xg@mail.gmail.com/ Signed-off-by: Caleb Sander Mateos --- drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h b/drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h index 4b7f7131c560..f03736711343 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/lib/eq.h @@ -68,13 +68,12 @@ static inline struct mlx5_eqe *next_eqe_sw(struct mlx5_eq *eq) static inline void eq_update_ci(struct mlx5_eq *eq, int arm) { __be32 __iomem *addr = eq->doorbell + (arm ? 0 : 2); u32 val = (eq->cons_index & 0xffffff) | (eq->eqn << 24); - __raw_writel((__force u32)cpu_to_be32(val), addr); - /* We still want ordering, just not swabbing, so add a barrier */ - mb(); + /* Ensure ordering of consecutive doorbell writes */ + writel((__force u32)cpu_to_be32(val), addr); } int mlx5_eq_table_init(struct mlx5_core_dev *dev); void mlx5_eq_table_cleanup(struct mlx5_core_dev *dev); int mlx5_eq_table_create(struct mlx5_core_dev *dev); From patchwork Fri Nov 1 03:46:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Caleb Sander Mateos X-Patchwork-Id: 13858680 Received: from mail-yw1-f226.google.com (mail-yw1-f226.google.com [209.85.128.226]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2404D13C67C for ; Fri, 1 Nov 2024 03:48:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.226 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730432908; cv=none; b=fh/NqdJOvquEKxjPSoNreAFzLNJM2ppByKOJxnokJi1Ah1Cc2XaQOXh3+dYqlIQ0xZ43q3xgh/kptlY4KwUrs9txxJ9Gvd52ENmmjQ7eattdF3CTcTBr6xiO4fvdlHo0xtDQt/LyyKtsAqiLuSgYtFPOOmIddMUl2fFNceBsWvI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730432908; c=relaxed/simple; bh=vb2oy9sCtacw/TXgOT7kaZXJblOW4SHOKBYJ4mHT4RA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YXqGLU8kCurkqyYGJORSm+z3g8o4qcWIYbQovGtQDJp5JHqqtrjKsrp5zBCVxPXc8L4218E71S1kKz4xUMt9Vy04vEi/BExe4JLzVFiPSSon7n6H40OuN3EZOyAuMHPd5AZrYDjHHpt1zxpHnq56HUHAJZ0TVfNDbbYNIqzWGzA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com; spf=fail smtp.mailfrom=purestorage.com; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b=ZzeeFI5G; arc=none smtp.client-ip=209.85.128.226 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=purestorage.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=purestorage.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=purestorage.com header.i=@purestorage.com header.b="ZzeeFI5G" Received: by mail-yw1-f226.google.com with SMTP id 00721157ae682-6e36a012af3so777587b3.3 for ; Thu, 31 Oct 2024 20:48:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=purestorage.com; s=google2022; t=1730432904; x=1731037704; 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=Up78lUxvH9q9ucvQFWkY0ZlRiNJvCC25wLA/XPV5mzI=; b=ZzeeFI5Gv+utldo5Ncc9JuDW9O2ij/nWykM+hYt3eacndZW+NQ2BgmlNiNuWeyOg3z VmZ6RbAqMHKer7PLU3pANnTSi0JvOge7NAz6yU3+MOMLsOLPORib6vkZju2+ZwQam9hO EQwYMKA5/LAAuf8rlWlk1kf/LhfmHmMivG/z7x+ved8Hh3Swa4z/FuE+WOVAKSzdoTEx b6hv0YBZPQOa0kpds8oyLWvKPAWvGeA01YEZSawMCADj6w/7dB/9gHgp2zO+rJvKkWPr qTpew1XhDbvPSccrOy6RULbCI707Rk0kgJmZ4HJIqCt1RlIPGeRiMzb0926tSUFUDfLg UYuQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730432904; x=1731037704; 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=Up78lUxvH9q9ucvQFWkY0ZlRiNJvCC25wLA/XPV5mzI=; b=cIzu6C0Mqy+RRlB1CAlxkgzd8fXvc80xQY0QSdA3a6I7VkRicshLlFdGuEu5VldOlE KsF2XzqGjYLH03vFT48dIKNAcpHxkEdMbl+953SZ8fDMzvSSvuWMqXqUBr2tkPzlYTM5 AoqX5KVGrz/pWNfAwvrHwPJ4iAneU8UU6c38XV7zn4nWH+vfESQMlm+JbCJGY4OeK2yP ds+kHmCB4uyaUIYqnzqGJcdk/SxLVEJPCVIw+7R9JEzBopk+tr2XCamAl0dGPyeHwoCE TLe1FexOWBT6CqFGrazUJUne81WMy5YXaNHM/G5MpvcD3myIBBtaiIm0MySp8U44GdMG dVjA== X-Forwarded-Encrypted: i=1; AJvYcCXfb+/Uo7gokOsdoDQZOuZ1aykCmqjaQLitZHd/Nni97Xxz2pR967Gn9oE/iFAc++xGRY6Scg5HGlEF@vger.kernel.org X-Gm-Message-State: AOJu0YzHisCD1pkqmnp392gvaaa0l3w61HrSNW4QHjXgCo5lUkYtnmGf 8VGg26w0C/ds8ag+to7vcNl7sE9NWSEm8fcCrHegd4+NwMk+Xhj3oiIKq8NrBC5QOSdLQVX2Bl6 8pSoe/OC8e1ZnrUy7+1gDRng8FsEDbfGDz5bWqykPMHS6+qfg X-Google-Smtp-Source: AGHT+IGWZ6+2TcpibDq+QvmilpiTPyrL6xq18JN2Nx0c+o1Cryy+xInZp0VbeTqIdLLnK+T9JrTGA/dbML47 X-Received: by 2002:a05:690c:fc7:b0:6e2:ad08:492a with SMTP id 00721157ae682-6e9d8aab833mr104947587b3.5.1730432903988; Thu, 31 Oct 2024 20:48:23 -0700 (PDT) Received: from c7-smtp-2023.dev.purestorage.com ([2620:125:9017:12:36:3:5:0]) by smtp-relay.gmail.com with ESMTPS id 00721157ae682-6ea55b0cd8fsm946117b3.20.2024.10.31.20.48.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Oct 2024 20:48:23 -0700 (PDT) X-Relaying-Domain: purestorage.com Received: from dev-csander.dev.purestorage.com (dev-csander.dev.purestorage.com [10.7.70.37]) by c7-smtp-2023.dev.purestorage.com (Postfix) with ESMTP id A182A3406A8; Thu, 31 Oct 2024 21:48:22 -0600 (MDT) Received: by dev-csander.dev.purestorage.com (Postfix, from userid 1557716354) id 98397E42B1D; Thu, 31 Oct 2024 21:48:22 -0600 (MDT) From: Caleb Sander Mateos To: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Caleb Sander Mateos , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next 2/2] mlx5/core: deduplicate {mlx5_,}eq_update_ci() Date: Thu, 31 Oct 2024 21:46:40 -0600 Message-ID: <20241101034647.51590-2-csander@purestorage.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241101034647.51590-1-csander@purestorage.com> References: <20241101034647.51590-1-csander@purestorage.com> Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The logic of eq_update_ci() is duplicated in mlx5_eq_update_ci(). The only additional work done by mlx5_eq_update_ci() is to increment eq->cons_index. Call eq_update_ci() from mlx5_eq_update_ci() to avoid the duplication. Signed-off-by: Caleb Sander Mateos --- drivers/net/ethernet/mellanox/mlx5/core/eq.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/eq.c b/drivers/net/ethernet/mellanox/mlx5/core/eq.c index 859dcf09b770..078029c81935 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/eq.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/eq.c @@ -802,19 +802,12 @@ struct mlx5_eqe *mlx5_eq_get_eqe(struct mlx5_eq *eq, u32 cc) } EXPORT_SYMBOL(mlx5_eq_get_eqe); void mlx5_eq_update_ci(struct mlx5_eq *eq, u32 cc, bool arm) { - __be32 __iomem *addr = eq->doorbell + (arm ? 0 : 2); - u32 val; - eq->cons_index += cc; - val = (eq->cons_index & 0xffffff) | (eq->eqn << 24); - - __raw_writel((__force u32)cpu_to_be32(val), addr); - /* We still want ordering, just not swabbing, so add a barrier */ - wmb(); + eq_update_ci(eq, arm); } EXPORT_SYMBOL(mlx5_eq_update_ci); static void comp_irq_release_pci(struct mlx5_core_dev *dev, u16 vecidx) {