Linux clocksource tsc. 1 基于 turbostat （不推荐） 4. 8. name = "tsc", . At least AWS have now included it in their recommendations. Some applications depend on clock resolution, and a clock that delivers reliable nanoseconds readings can be One advice that worked for some was to use clocksource=hpet or clocksource=acpi_pm. At least, I think mapping the clocksource information structure itself in some kind of sharable page makes sense . 960048] Clocksource tsc unstable (delta = -105611479 ns) I found some resources on the net, and it said to change clocksource, or disable ACPI. As of BIOS 1. > > I just built an unpatched linux v4. 12 serial: <superuser required> Mobo I understand that tsc isn't considered to be accurate with modern CPUs because of throttling/power saving features but /proc/cpuinfo tells that the processors seen by the VM have the constant_tsc flag. 4 查看和监控 TSC 相关信息 4. 2 turbostat 查看实际 TSC 计数（可能不准） 4. 04 noble Machine: Type: Laptop System: Acer product: Extensa 2540 v: V1. Also, while I often post about superpower tracing tools, sometimes some humble hacking is best. 35, the time stamp counter (TSC) can be unusable on a cold boot, as indicated by the following log output: $ dmesg | grep -i tsc [ 0. When the clocksource watchdog detects too much drifts or skews from the unreliable TSC, it tags it as unstable. 9 and recent versions of QEMU, it is now possible to passthrough a graphics card, offering the virtual machine native graphics performance which is useful for graphic-intensive tasks. Hardware clocks Copy linkLink copied to clipboard! Multiple instances of clock sources found in multiprocessor systems, such as non-uniform memory access (NUMA) and Symmetric multiprocessing (SMP kvm-clock tsc acpi_pm You are currently using “tsc” as per the initial output error, try using “acpi_pm” first, if you are under a KVM environment, you can try out “kvm-clock”. 2 执行效果 4. 6. Could you give the boot log? Look for /var/log/boot. 10 has new code which utilizes the TSC_ADJUST MSR. When a Linux guest detects that this Hyper-V functionality is available, it prefers to use Linux’s standard TSC-based clocksource. > sched_clock: Marking unstable (1950347883333462, 79649632569)<- (1950428279338308, -745776594) > clocksource: Checking clocksource tsc synchronization from CPU 400 to CPUs 0,46,52,54,138,208,392,397. /tlgtd it worked! - GTOD: clock:1 mult:5798662 shift:24 synced - mult now But please, can anyone tell me if are there any plans to move the time infrastructure out of the kernel and into glibc along the lines outlined in previous mail - if not, I am going to concentrate on this more radical overhaul approach for my own systems . What does this message Chapter 15. 第15章 タイムスタンプ | リファレンスガイド | Red Hat Enterprise Linux for Real Time | 7 | Red Hat Documentation 起動時に、カーネルは利用可能なクロックソースを検出し、使用するクロックソースを選択します。希望するクロックソースは Time Stamp Counter (TSC) ですが、利用できない場合には、HPET (High Precision 2. Part 2. If the override is successful, then the clocksource: Switched to clocksource tsc message appears. ubuntu. How to check what clock source is currently in use by the system How to override system's configuration specifying a particular clock source How to modify the system time How to configure high precision time Oracle recommends that you set the clock source to tsc for better performance in virtual environments (VM) on Linux x86-64. Managing system clocks to satisfy application needs | Optimizing RHEL 8 for Real Time for low latency operation | Red Hat Enterprise Linux for Real Time | 8 | Red Hat Documentation 12. 今回は、current clocksourceの設定確認～変更の方法までまとめて説明していきたいと思います。 そもそもclocksourceとは clocksourceとは、ざっくり言うとOSが時刻を取得するためのソースのことを指し、current clocksourceとはその名の通り現在設定されているclocksourceのことを指します。 clocksourceにはXen Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! [ 6. 367627] clocksource: Switched to you could try booting with another clock, eg clocksource=hpet if you think it will change things. It counts the number of CPU cycles since its reset. Identical servers running Redis showed puzzling latency spikes and CPU overloads, all traced to Linux's clocksource settings. The last message is switched to clocksource tsc My laptop is a ASUS Zenbook UX430 UA. Note: If you reboot the system, then the Linux kernel resets the clock source. Hello, In /var/log/syslog I noticed this; Code: May 9 19:50:36 slack kernel: clocksource: timekeeping watchdog on CPU3: Marking clocksource 'tsc' as Linux stops at "Switched to clocksource tsc" after fresh install of 14. 765438] clocksource: timekeeping watchdog on CPU1: Marking clocksource 'tsc-early' as unstable because the skew is too large: [ 1. Title: Ubuntu 14. Using Hardware Clocks for System Timestamping | Tuning Guide | Red Hat Enterprise Linux for Real Time | 7 | Red Hat Documentation Requirements for crucial applications vary on each system. 04 noble Machine: Type: Desktop System: ASUS product: N/A v: N/A serial: <superuser required> Mobo: ASUSTeK On 22/02/2017, Jason Vas Dias < [email protected] > wrote: > RE: >>> 4. X86 平台提供读取tsc的指令 rdtsc/rdtscp 可以用户态轻量获取tsc的值。相比vsdo提供的gettimeofday更高效。可靠性 - reliable_tsc但是了解下来，tsc有其弊端，作为时钟源存在很多问题： 频率受cpu频率影响，进入C-… Checking the messages log I have observed they all have "clocksource tsc unstable" then "Time: acpi_pm clocksource has been installed". I can't change clock to hpet, because my system doesn't have such one. 0-52-generic arch: x86_64 bits: 64 compiler: gcc v: 13. launchpad. 0 clocksource: tsc Desktop: Cinnamon v: 6. conf. The preferred clock source is the Time Stamp Counter (TSC), but if it is not available the High Precision Event Timer (HPET) is the second best option. 0 Host bridge: Advanced Micro Devices, Inc. notes and example codes on using rdtsc(p) instructions for benchmarking - xuwd1/rdtsc-notes PCI passthrough via OVMF The Open Virtual Machine Firmware (OVMF) is a project to enable UEFI support for virtual machines. tscsync=1 to the GRUB_CMDLINE_LINUX variable. 3. 4 监控 4. 121473] tsc: Marking TSC unstable due to clocksource watchdog [ 6. [AMD] Raphael/Granite Ridge Root Complex 00:01. It does seem a little redundant that the Linux APIC code goes to these lengths to check that the legacy 8254 timer interrupt is working before it then gets disabled a bit later during boot (when setup_APIC_timer happens, the clocksource layer disables the previous timer source, in this case the PIT or HPET). It partly pertains to the drivers usually found in drivers/clocksource in the kernel tree, but the code may be spread out across the kernel. Just try, it's easy. 121612] clocksource: Checking clocksource tsc synchronization from CPU 6 to CPUs 0,9-12. rating = 300, When a Linux guest detects that this Hyper-V functionality is available, it prefers to use Linux’s standard TSC-based clocksource. 10 with tglx's TSC improvements - > much else improved in this kernel (like iwlwifi) - thanks! > > I have attached an updated version of the test program which > doesn't print the bogus Hi, I have this issue on Toshiba Chromebook CB30. I am using the 3. Timestamping | Reference Guide | Red Hat Enterprise Linux for Real Time | 7 | Red Hat Documentation During boot time the kernel discovers the available clock sources and selects one to use. After these all three clock sources will be registered in the clocksource framework and the Time Stamp Counter clock source will be selected as active, because it has the highest rating among other clock sources: static struct clocksource clocksource_tsc = { . 6解読室」などのLinuxカーネル本では、Linuxカーネルの時刻管理について、超絶に要約すると次のように説明されています。 一定の時間間隔（1000Hz）でタイマ割り込みが入る。 タイマ割り込みごとにjiffies変数を1増やす（つまり、jiffiesは、システム Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! tsc: Refined TSC clocksource calibration 2994. net/ubuntu/+source/linux/+bug/1308264/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists. 146577] clocksource: Switched to clocksource tsc-early [ 1. Why are "Clocksource tsc unstable" warnings displayed in RHEV hosts? Apr 12 13:26:02 rhevh1 kernel: Clocksource tsc unstable (delta = -8589933168 ns). All these messages happened around a moment of system time adjustment by one of our applications that keeps server time in sync with a remote system once in a while. I just built an unpatched linux v4. [AMD] Raphael/Granite Ridge Dummy Host Bridge 00:01. With linux kernel 3. mstflint is a collection of Linux tools from Mellanox, which lets you query and flash firmware but also includes diagnostic and configuration tools for their switches and network cards. CentOS7支持多种时钟源，如 tsc 、 hpet 、 acpi_pm 等。 一般来说， tsc （Time Stamp Counter）时钟源在大多数现代硬件上表现最佳。 4. Therefore, the best clock for each application, and consequently each system, also varies. 1 tsc：优先 4. log or do a grep "Apr 14" /var/log/messages. 748 MHz processor [ 0. Apr 12 14:45:14 rhevh1 kernel: Clocksource tsc unstable (delta = -8589932928 ns). Open the /etc/default/grub file in your preferred text editor and append the parameters clocksource=tsc powernow-k8. 15 linux kernel with some patches for the trackpad. 10 with tglx's TSC improvements - much else improved in this kernel (like iwlwifi) - thanks! System: Kernel: 6. 1 Linux 系统时钟源（clocksource）配置 4. 000000] tsc: Fast TSC calibration using PIT [ 0. I tried disabling ACPI but it didn't help (but I noticed there was longer time before hanging). 000000] tsc: Detected 1696. Jul 29 22:38:58 leonidas kernel: [ 91. 7k次。本文详细介绍了Linux内核在x86_64架构下如何初始化和使用不同的时钟源，包括TSC（TimeStampCounter）、HPET（HighPrecisionEventTimer）和ACPI PM（PowerManagementTimer）。文章通过源码分析了它们的频率、初始化过程和在系统中的角色，强调了TSC作为最高评级的时钟源。 Oracle recommends that you set the clock source to tsc for better performance in virtual environments (VM) on Linux x86-64. False Positive in the log: Linux is not using a fast TSC clock source #41199 Closed melvynator opened on Sep 12, 2022 2. 文章浏览阅读4. Apr 12 14 Not sure why TSC as a clock source is not available? cat /sys/devices/system/clocksource/clocksource0/available_clocksource hpet acpi_pm The CPU I'm using is Intel Time Stamp Counter A Linux boot log showing the usage of TSC as system clocksource The Time Stamp Counter (TSC) is a 64-bit register present on all x86 processors since the Pentium. 0 Distro: Linux Mint 22. This deep dive reveals why HPET is a silent killer for high-throughput workloads and provides actionable fixes to lock in TSC for optimal performance. 765440] clocksource: 'refined-jiffies' wd_nsec: 512032000 wd_now: fffedc08 wd_last: fffedb88 mask: ffffffff Chapter 12. I had the same problem with Virtual Box but this command "vboxmanage setextradata Probably solved the issue: by setting the tsc=unstable kernel boot parameter, and re-enabling HPET in the UEFI/BIOS, the Linux kernel decided to use hpet as clocksource since boot time and has been running fine for around a week. 04 -- Setup or reinstall? Ask Question Asked 11 years, 9 months ago Modified 1 year, 7 months ago 「詳解 Linuxカーネル 第3版」や「Linuxカーネル2. 17. 1 PCI bridge: Advanced Micro Devices, Inc. 04 Beta 2 stuck at "Switched to clocksource tsc" when booting up, then resumes booting to the login screen, after 1 minute To manage notifications about this bug go to: https://bugs. 3 Zena base: Ubuntu 24. However, not all systems have HPET clocks The vsyscall_gtod_data. Processes could map that RE: >> 4. 2 hpet：性能开销太大 4. 6 tk: GTK v: 3. 30. 1 Xia base: Ubuntu 24. If you still don't see a table here, or a table filled with '¿': Is there already a Techdata page available for Deciso DEC740 ? If not: Create one Clock sources, Clock events, sched_clock () and delay timers ¶ This document tries to briefly explain some basic kernel timekeeping abstractions. [AMD] Raphael/Granite Ridge GPP Bridge Subsystem: Advanced Micro Devices, Inc 時刻がずれたエラーがでたということで備忘録を。 うるう秒対策の-xオプションのせいで一気にあわないのと ハードウェアクロックとの同期もできないのでどんどんずれてってました。 Apr 13 13:36:40 localhost kernel: Clocksource tsc [ 0. Otherwise, it uses the clocksource for the Hyper-V synthetic system clock implemented via the shared page (identified as “hyperv_clocksource_tsc_page”). 更改时钟源 要更改时钟源，可以在GRUB配置文件中添加相关参数。 编辑 /etc/default/grub 文件，添加如下内容： GRUB_CMDLINE_LINUX="clocksource=tsc" For Linux I've been recommending the faster tsc clocksource for years, altough I'm not a processor vendor so I can't make assurances about tsc issues of clock drift. 121470] clocksource: 'tsc' is current clocksource. TSC clocksource : ユーザーランドで特定の CPU レジスタから時刻を読み取る。 Linux Kernel や Xen hypervisor の呼び出しを伴わないので速い Xen clocksource (Amazon Linux デフォルト): Kernel 経由で Xen の hypervisor から時刻を取得する。 Kernel や hypervisor への切替を伴うので遅い。 Timers and time management in the Linux kernel. 2. If the server hangs or turns off it may be hardware problems like power supplies, fan failure, overheating due to dry thermal paste, and so on. This forces the use of TSC and enables simultaneous core processor frequency transitions. 14 this issue is gone but my trackpad does not work. The instruction RDTSC returns the TSC in EDX:EAX. [AMD] Raphael/Granite Ridge Root Complex Subsystem: Advanced Micro Devices, Inc. Introduction to the clocksource framework The previous part was the first part in the current chapter that describes timers and time management related stuff in the Linux kernel. During installation XCP-ng 8. In x86-64 mode, RDTSC also clears the upper 32 bits of RAX and Use 'tsc=unstable'. If you grep through the kernel source you will find a number of architecture- specific implementations of The file /sys/devices/system/clocksource/clocksource0/available_clocksource in my Linux box lists the following clock sources: tsc hpet acpi_pm I know that tsc is the . Obviously TSC and HPET are firmware/hardware level functionality that the kernel is already dealing with. 1 C 代码 4. ” instead of a table, please edit this section and adjust the filters with the proper Brand and Model. If the underlying hardware, hypervisor and guest OS linux kernel support Invariant TSC, tsc will be offered as available and supported clock source in the guest OS on Azure VMs. 3 vt: 7 dm: LightDM v: 1. Info This table is automatically generated, once the correct filters for Brand and Model are set. mult field changes somewhat between calls to clock_gettime (CLOCK_MONOTONIC_RAW,&ts), so that sometimes an extra (2^24) nanoseconds are added or removed from the value derived from the TSC and stored in 'ts' . com/mailman System: Kernel: 6. 160394] clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x18752743c99, max_idle_ns: 440795215663 ns [ 0. 2 基于 rdtscp Hyper-V TSC page (hyperv_clocksource_tsc_page) is supported on all Azure VMs as a clock source. h 3) TSC stability From the kernel point of view: An unreliable TSC means there is a suspicion that something bad can happen with the clocksource. 7 tk: GTK v: 3. 41 wm: Muffin v: 6. This is demonstrated by the output of the test program in the attached ttsc. 0-14-generic arch: x86_64 bits: 64 compiler: gcc v: 13. 121664] clocksource: Switched to clocksource hpet DMI: ASUSTeK COMPUTER INC. Enable clocksource failover by adding clocksource_failover kernel parameter. 1, installation stuck at "clocksource: Switched to clocksource tsc". RHEL8/9: tsc: Marking TSC unstable due to clocksource watchdog after CPUs are added online Solution Verified - Updated June 13 2024 at 7:57 PM - English 00:00. In another thread, someone fixed this with clocksource=jiffies, another advised to try noapic or nolapic, another to turn acpi off in the BIOS, and still another blamed the Synaptics touchpad and fixed his problem by deleting Xorg. 380 MHz clocksource: tsc: mask: 0xfffffffffff max_cycles: 0x2b298873dd8, max_idle_ns: 440795219646 ns clocksource: Switched to clocksource tsc In fact, your system is not hanging on "switching to clocksource tsc" but on the step after! The one that takes a long long time to get printed. [ 6. 3 rdtsc/rdtscp 指令采集 TSC 计数 4. Whenever I see Linux booting, I see this message: clocksource tsc unstable (delta = NNNNNNNN ns) where NNNNNNNN is some very large number which may be positive or negative. An unstable TSC means that something bad has eventually happened with the clocksource. 1 vt: 7 dm: LightDM v: 1. But Linux has a special-case performance optimization for time calls. 24. tar file: $ . > clocksource: Switched to clocksource hpet The measured clocksource skew - the absolute difference between cs_nsec Linux kernel freezes on clocksource tsc Hello, Im trying to install Ubuntu (already tried other distros), but with each distro, the kernel already freezes on the point of booting the live usb. If you see “Nothing. Starting with Linux 3. We got acquainted with two concepts in the previous part: jiffies clocksource The first is the global variable that is defined in the include/linux/jiffies. 4. 1. nlrgu, xbe5pb, w5kavk, erkg, qapa, meqxi, dzyijo, ujre, azx1sn, uzvd,