From patchwork Sat Aug 26 11:28:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Wahren X-Patchwork-Id: 717507 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 AC0D3C83F01 for ; Sat, 26 Aug 2023 11:30:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232613AbjHZL3u (ORCPT ); Sat, 26 Aug 2023 07:29:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232160AbjHZL3c (ORCPT ); Sat, 26 Aug 2023 07:29:32 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4128D1BF2 for ; Sat, 26 Aug 2023 04:29:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=s31663417; t=1693049347; x=1693654147; i=wahrenst@gmx.net; bh=rPNVIq+eiEBeeUY1NCey4A6+NK7K5p71Kf2k0g5gw+M=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date; b=RleJzVedYE3/dHrDI1xRjqYhRiktqLwYExai6EmsnTrwoE99FX7BkWCTuX/mU1Dx/Hsx8+J vRXgY0MLMSQKe2LWGBMidX4Q86r+H4L1M5OYikVXaJoROq7+kPX0kGxWcwyx3s8wG7/MlebiX A0fxk/oWFLWu39DTN11yYt38sI81gwwLWkXe+90oswHpPRs6i3t4OX/h7HKUTeQFq9iHr04Js W4yQXYBjVqW7DkWv/yoJX+TPC1IhIg3wFRfQZfzQRzPQZ+DAkNZ8JyNgTkZYRHeGhvv9YaTC9 R5NP2tWA01eQSNNQ7x5LtywWJqFpupRWtrs+Nls/KvUnTUXLNCdA== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from stefanw-SCHENKER ([37.4.248.43]) by mail.gmx.net (mrgmx104 [212.227.17.168]) with ESMTPSA (Nemesis) id 1MqJqN-1pwNs00U55-00nUXT; Sat, 26 Aug 2023 13:29:07 +0200 From: Stefan Wahren To: Olivia Mackall , Herbert Xu , Florian Fainelli , Ray Jui , Scott Branden Cc: "Jason A. Donenfeld" , Mark Brown , linux-crypto@vger.kernel.org, linux-arm-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, Stefan Wahren Subject: [PATCH] hwrng: bcm2835: Fix hwrng throughput regression Date: Sat, 26 Aug 2023 13:28:28 +0200 Message-Id: <20230826112828.58046-1-wahrenst@gmx.net> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Provags-ID: V03:K1:kqpr+9dJcQrDIhh/bO6mypwC9b8arJqYymbe/xO7CxS8U4OmV4t qc1fjA78boX0Wr0PHMmJddws2b+71QBacs6pitWWb6EX+E1Dkg4/4k9jsGGYyCcH5hjtwzb OmIuAUuaZkU7oc8S08KDWIH7j1nzZVT6vTk1Ne+yWA4vpDE3LA5RptgR+88CxYBoplPhxUJ ZOrn4g0Fn2tLCM3TwLOcg== UI-OutboundReport: notjunk:1;M01:P0:+VJbH5XzvYY=;mGOT4IZLYs7jNNQ2wMvfi+y1drJ qM9WMuuJL8wqSSA6z8bzQa8TX/3ZxZMCXJW/G8BJ1LQC9oKlG9MMLs7gOf+VrXcnXWZybpkJN fjlvn9NoUI1/CUs9jIl7cFrFLfhNIUVNnk/S8kHt7ZcROxl9qE3PPS/6kSR4iser9q7riBJE9 EV3/kmFbi1z53PmFQStUJteryCSl/3IFnRJPcUt5v4wDp0PxahDOD6s2xb8FD127B20d5KG1g S+x/iAvs9maebVHnGcWfag5MBX3vVSDs90/PIoQcN8IHgfrLGddzoPKQ5YNCQtijgpMS/mvX4 X2gt+G3uqwOhm4Bdk0kPDctvZoKFkngHqHA+PibDgkiR7Um8eIDWnO5Zd0bm/qPPyAU2ukRff w882Ro4AQ8jgzgD/ii3qucCKWh6KEnf2vbeXNebDP51V5Z9SdkUPG0pydi5xJCrhS+B//AnSv n8tDdXw1mrzgVNG09hi/Crca8iNFB5PKs97ubEvW7fjVo/DMPLci8a+TTVC99VrNboHZ27p6P 6yzg/IM/2GUMO+0IpXlJAzNynUrNXK/TEQtmliSaF80Ml4EQmYnGsT5VLJODDqFeyEhLskIh2 p/BEU6Wz1wFD15Aj76D0ITSVUjN9A3QAuX+0aUTAGrsnyUf03J1IQWGA6GbjTJDfh0EdFS7f6 z+kp5PvuiwqT/4OOPOEY86KOG6K3llUEcFuPNX7GxrrgN51cDewMjr3V3/hGynu1IsEhOc90x bEivI7etZO8C8JVdc0jnBQR8EdCcJakdIfh5i78x/BH0OPn6E9WfT5Q7iBoIWTGE3ibY/Xnkr s3hdQwv76ew1aO4RSPx5SpnBG/mVs6n6HWhf+IoS3ytocpU+FC00s6znjPtKV12p5+qDiL7e4 DsZ5DBKMmAq1Aw5qnDP+VhScfLLBTnybS5k/5Qwlegn55nGxKMr6NONAQy4KX/85HYmnnf4GI Nk2UdQ== Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The recent RCU stall fix caused a massive throughput regression of the hwrng on Raspberry Pi 0 - 3. So try to restore a similiar throughput as before the RCU stall fix. Some performance measurements on Raspberry Pi 3B+ (arm64/defconfig): sudo dd if=/dev/hwrng of=/dev/null count=1 bs=10000 cpu_relax ~138025 Bytes / sec hwrng_msleep(1000) ~13 Bytes / sec usleep_range(100,200) ~92141 Bytes / sec Fixes: 96cb9d055445 ("hwrng: bcm2835 - use hwrng_msleep() instead of cpu_relax()") Link: https://lore.kernel.org/linux-arm-kernel/bc97ece5-44a3-4c4e-77da-2db3eb66b128@gmx.net/ Signed-off-by: Stefan Wahren --- drivers/char/hw_random/bcm2835-rng.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.34.1 diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c index e98fcac578d6..3f1b6aaa98ee 100644 --- a/drivers/char/hw_random/bcm2835-rng.c +++ b/drivers/char/hw_random/bcm2835-rng.c @@ -14,6 +14,7 @@ #include #include #include +#include #define RNG_CTRL 0x0 #define RNG_STATUS 0x4 @@ -71,7 +72,7 @@ static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max, while ((rng_readl(priv, RNG_STATUS) >> 24) == 0) { if (!wait) return 0; - hwrng_msleep(rng, 1000); + usleep_range(100, 200); } num_words = rng_readl(priv, RNG_STATUS) >> 24;