From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 2A2EB459ED; Sat, 21 Sep 2024 16:00:37 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4C308402C6; Sat, 21 Sep 2024 16:00:34 +0200 (CEST) Received: from mail-ej1-f47.google.com (mail-ej1-f47.google.com [209.85.218.47]) by mails.dpdk.org (Postfix) with ESMTP id BE584402C0 for ; Sat, 21 Sep 2024 16:00:33 +0200 (CEST) Received: by mail-ej1-f47.google.com with SMTP id a640c23a62f3a-a8d6ac24a3bso506789666b.1 for ; Sat, 21 Sep 2024 07:00:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1726927233; x=1727532033; darn=dpdk.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=2iBh6AANd4YBihDJlFvgCGHVmrRnV7fOd8T3j5al8gQ=; b=YWgM3JeLwSOu2BoGDMOzlB5pz0I9IOE3zks/pOP2uWFXZkuZoAtVVAlv7yrBMVel03 /QG4Z2OtumudazUL5oKBmKxoNkhcA9KPw8ltCV0zGuVAjiLiGjkeF+YweGooX+4bZEGa OqzXMOkfuseO/vJvecMhSx2i17mYZxFYMiba8LjKiVfZt439NNxN5Tu8uUtQL6qCVFyR wQtDzeMVDVLqRZkr3j+t0TUAXViskhfCaN2HTzMUMO+QV+QDseAHFxSsTrVawC+JVIXZ Nx4FIz/ykHq8h+9w0If32bX3k6Bn7inkMaTwDTgu6CS28pEczbkclU0f9O9H6RaOsRY3 w2tA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726927233; x=1727532033; 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=2iBh6AANd4YBihDJlFvgCGHVmrRnV7fOd8T3j5al8gQ=; b=xUWMtAyzbOcO4QIQ5pWkIYSGyhfsW0/m264ulbbXZRLxRdGTqwv2Fw38nKBe4eHFT7 eNR3FdBaIKQL0NDAEuMBdcIFIXyWdIvPodgd0vOo16Szh1Hw3YNh1dTVtyeKZM73DkcF 508vF5hib/OoNMe9Bop8OA7Fx+d9Shyw5s0BdMrjxNuKV4CiHNk5p2q6EpqQdb/+3JGP 1zv70DFjzpF5E14BJpo/a4AIWRxJVxxoZXagFE8I2D1Kjca3KYLpIGn3CJ9A3q93k6E/ K52Jhx1jAueX1UgO8Hh7HyXa84q1UHCTZ5ztzf2OxEIld8HQ8B8GSi6qzzk3YeCjIFDD I+sQ== X-Gm-Message-State: AOJu0YxdWm8+HL+8Ha/kADXBPd0vdeOYqz84q536Y6NVSpjcathWvog7 Kzbu3cz5ECn1XgQKWpD4PkXD1f6XrUmvLZpRcF1bcXZx+dFU60b0L38S2Bxf X-Google-Smtp-Source: AGHT+IFBU9iWIm3YC01RHKtq8Yh6LfMo3ceU/yAP0YwdPI3GkUAj5XyN0griONShEoPh5wYcSvg8Dw== X-Received: by 2002:a17:907:1c90:b0:a77:ab9e:9202 with SMTP id a640c23a62f3a-a90c1c38504mr1014685266b.4.1726927232820; Sat, 21 Sep 2024 07:00:32 -0700 (PDT) Received: from localhost.localdomain ([176.13.142.196]) by smtp.googlemail.com with ESMTPSA id a640c23a62f3a-a90612df5cfsm993153766b.146.2024.09.21.07.00.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 21 Sep 2024 07:00:32 -0700 (PDT) From: Isaac Boukris To: dev@dpdk.org Cc: stephen@networkplumber.org, Isaac Boukris , Tyler Retzlaff , Bruce Richardson , Dmitry Kozlyuk , Pallavi Kadam Subject: [PATCH 2/2] timer/linux: override TSC freq if no tsc_known_freq Date: Sat, 21 Sep 2024 17:00:22 +0300 Message-ID: <20240921140022.107239-2-iboukris@gmail.com> X-Mailer: git-send-email 2.45.0 In-Reply-To: <20240921140022.107239-1-iboukris@gmail.com> References: <20240921140022.107239-1-iboukris@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org If the tsc_known_freq cpu flag is missing, it means the kernel doesn't trust it and calculates its own. We should do the same to avoid drift. Signed-off-by: Isaac Boukris --- lib/eal/common/eal_common_timer.c | 3 +- lib/eal/common/eal_private.h | 2 +- lib/eal/freebsd/eal_timer.c | 5 +++- lib/eal/linux/eal_timer.c | 48 +++++++++++++++++++++++++++++-- lib/eal/windows/eal_timer.c | 5 +++- 5 files changed, 56 insertions(+), 7 deletions(-) diff --git a/lib/eal/common/eal_common_timer.c b/lib/eal/common/eal_common_timer.c index c5c4703f15..e00be0a5c8 100644 --- a/lib/eal/common/eal_common_timer.c +++ b/lib/eal/common/eal_common_timer.c @@ -66,8 +66,7 @@ set_tsc_freq(void) } freq = get_tsc_freq_arch(); - if (!freq) - freq = get_tsc_freq(); + freq = get_tsc_freq(freq); if (!freq) freq = estimate_tsc_freq(); diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h index af09620426..bb315dab04 100644 --- a/lib/eal/common/eal_private.h +++ b/lib/eal/common/eal_private.h @@ -374,7 +374,7 @@ void set_tsc_freq(void); * * This function is private to the EAL. */ -uint64_t get_tsc_freq(void); +uint64_t get_tsc_freq(uint64_t arch_hz); /** * Get TSC frequency if the architecture supports. diff --git a/lib/eal/freebsd/eal_timer.c b/lib/eal/freebsd/eal_timer.c index 3dd70e24ba..5a8aea03e1 100644 --- a/lib/eal/freebsd/eal_timer.c +++ b/lib/eal/freebsd/eal_timer.c @@ -26,12 +26,15 @@ enum timer_source eal_timer_source = EAL_TIMER_TSC; uint64_t -get_tsc_freq(void) +get_tsc_freq(uint64_t arch_hz) { size_t sz; int tmp; uint64_t tsc_hz; + if (arch_hz) + return arch_hz; + sz = sizeof(tmp); tmp = 0; diff --git a/lib/eal/linux/eal_timer.c b/lib/eal/linux/eal_timer.c index 241b20d416..cdbd191828 100644 --- a/lib/eal/linux/eal_timer.c +++ b/lib/eal/linux/eal_timer.c @@ -5,9 +5,9 @@ #include #include +#include #ifdef RTE_LIBEAL_USE_HPET #include -#include #include #include #endif @@ -187,8 +187,38 @@ rte_eal_hpet_init(int make_default) } #endif +/* Check if the kernel deems the arch provided TSC frequency trustworthy. */ + +static bool +is_tsc_known_freq(void) +{ + char line[2048]; + FILE *stream; + bool ret = true; /* Assume tsc_known_freq */ + + stream = fopen("/proc/cpuinfo", "r"); + if (!stream) { + EAL_LOG(WARNING, "Unable to open /proc/cpuinfo"); + return ret; + } + + while (fgets(line, sizeof(line), stream)) { + if (strncmp(line, "flags", 5) != 0) + continue; + + if (!strstr(line, "tsc_known_freq")) + ret = false; + + break; + } + + fclose(stream); + + return ret; +} + uint64_t -get_tsc_freq(void) +get_tsc_freq(uint64_t arch_hz) { #ifdef CLOCK_MONOTONIC_RAW #define NS_PER_SEC 1E9 @@ -199,6 +229,9 @@ get_tsc_freq(void) struct timespec t_start, t_end; uint64_t tsc_hz; + if (arch_hz && is_tsc_known_freq()) + return arch_hz; + if (clock_gettime(CLOCK_MONOTONIC_RAW, &t_start) == 0) { uint64_t ns, end, start = rte_rdtsc(); nanosleep(&sleeptime,NULL); @@ -209,6 +242,17 @@ get_tsc_freq(void) double secs = (double)ns/NS_PER_SEC; tsc_hz = (uint64_t)((end - start)/secs); + + if (arch_hz) { + /* Make sure we're within 1% for sanity check */ + if (arch_hz - tsc_hz > arch_hz / 100) + return arch_hz; + + EAL_LOG(DEBUG, "Refined architecture frequency %"PRIu64 + " to actual frequency %"PRIu64".", + arch_hz, tsc_hz); + } + /* Round up to 10Khz. 1E4 ~ 10Khz */ return RTE_ALIGN_MUL_NEAR(tsc_hz, CYC_PER_10KHZ); } diff --git a/lib/eal/windows/eal_timer.c b/lib/eal/windows/eal_timer.c index b070cb7751..cfd6c267ac 100644 --- a/lib/eal/windows/eal_timer.c +++ b/lib/eal/windows/eal_timer.c @@ -49,13 +49,16 @@ rte_delay_us_sleep(unsigned int us) } uint64_t -get_tsc_freq(void) +get_tsc_freq(uint64_t arch_hz) { LARGE_INTEGER t_start, t_end, elapsed_us; LARGE_INTEGER frequency; uint64_t tsc_hz; uint64_t end, start; + if (arch_hz) + return arch_hz; + QueryPerformanceFrequency(&frequency); QueryPerformanceCounter(&t_start); -- 2.45.0