cpu

How does a CPU know if an address in RAM contains an integer, a pre-defined CPU instruction, or any other kind of data?

由 ≯℡__Kan透↙ 提交于 2020-07-09 08:44:40
问题 The reason this gets me confused is that all addresses hold a sequence of 1's and 0's. So how does the CPU differentiate, let's say, 00000100 (integer) from 00000100 (CPU instruction)? 回答1: First of all, different commands have different values (opcodes). That's how the CPU knows what to do. Finally, the questions remains: What's a command, what's data? Modern PCs are working with the von Neumann -Architecture ( https://en.wikipedia.org/wiki/John_von_Neumann) where data and opcodes are stored

Kubernetes CPU multithreading

由 情到浓时终转凉″ 提交于 2020-07-03 02:13:30
问题 I have a 4 cores CPU, I create a Kubernetes Pod with CPU resource limit 100m, which mean it will occupy 1/10 of a core power. I wondering in this case, 100m is not even a full core, if my app is a multithread app, will my app's threads run in parallel? Or all the threads will run in the part of core (100 milli core) only? Can anyone further explain the mechanism behind? 回答1: The closest answer I found so far is this one: For a single-threaded program, a cpu usage of 0.1 means that if you

CPU load percentage for individual processors

由 会有一股神秘感。 提交于 2020-06-28 03:59:08
问题 I am using following WMI query to get the CPU load percent data. Select * from win32_processor and below instance results are captured. Win32_processor WMI query results By above data it’s understood that there are two physical processor instances are available (CPU0 and CPU1). But it’s observed in some machines the load percent parameter for these instances always gives value as 100 and Microsoft has recommended to use the following WMI class to rectify this. So for the same machine below

How to properly use TSX-NI (both HLE and RTM) when threads might switch cores?

由 和自甴很熟 提交于 2020-06-27 11:55:46
问题 It seems that Intel's Transactional Synchronization Extensions (TSX-NI) work on a per-CPU basis. This applies to both the _InterlockedXxx_HLE{Acquire,Release} Hardware Lock Elision functions (HLE), as well as for the _xbegin / _xend /etc. Restricted Transactional Memory (RTM) functions. What is the "proper" way to use these functions on multi-core systems? Given their correctness guarantees, I assume I only need to be worried about performance here. So, how should I structure & write my code

how can I simulate cpu and memory stress in python

由 我的未来我决定 提交于 2020-06-26 04:45:26
问题 I would like to know if anyone wrote a code in python that simulates a cpu and memory stress. I saw a code loading the cpus, but how can I force them to work on 90% usage? 回答1: The below link answers the cpu stress. https://github.com/GaetanoCarlucci/CPULoadGenerator It appeared in that session: https://superuser.com/questions/396501/how-can-i-produce-high-cpu-load-on-windows/734782#734782?newreg=bec18b2f032a444187a8be7540ec6083 回答2: A node has mainly 4 resources that are under constant use -

Why is the branch delay slot deprecated or obsolete?

由 梦想的初衷 提交于 2020-06-12 06:40:30
问题 When I reading RISC-V User-Level ISA manual,I noticed that it said that "OpenRISC has condition codes and branch delay slots, which complicate higher performance implementations." so RISC-V don't have branch delay slot RISC-V User-Level ISA manual link. Moreover,Wikipedia said that most of newer RISC design omit branch delay slot. Why most of newer RISC Architecture gradually omit branch delay slot? 回答1: Citing Henessy and Patterson (Computer architecture and design, 5th ed.) Fallacy : You

Why not just predict both branches?

由 别等时光非礼了梦想. 提交于 2020-05-25 04:57:05
问题 CPU's use branch prediction to speed up code, but only if the first branch is actually taken. Why not simply take both branches? That is, assume both branches will be hit, cache both sides, and the take the proper one when necessary. The cache does not need to be invalidated. While this requires the compiler to load both branches before hand(more memory, proper layout, etc), I imagine that proper optimization could streamline both so that one can get near optimal results from a single

How does the CPU know how many bytes it should read for the next instruction, considering instructions have different lenghts?

由 删除回忆录丶 提交于 2020-05-15 06:54:05
问题 So i was reading a paper, and in it, they said that statically disassembling the code of a binary is undecidable, because a series of bytes could be represented as many possible ways as shown in picture ( its x86 ) so my question is : how does the CPU execute this then? for example in the picture, when we reach after C3, how does it know how many bytes it should read for the next instruction? how does the CPU know how much it should increment the PC after executing one instruction? does it

Get CPU temperature in CMD/POWER Shell

由 眉间皱痕 提交于 2020-05-08 04:45:08
问题 In my computer I am trying to get the CPU temperature. Searching on StackOverflow I found this: C:\WINDOWS\system32>wmic /namespace:\\root\wmi PATH MSAcpi_ThermalZoneTemperature get CurrentTemperature But I get this error: Node - ADMIN ERROR: Description = Not supported 回答1: you can use this code : function Get-Temperature { $t = Get-WmiObject MSAcpi_ThermalZoneTemperature -Namespace "root/wmi" $returntemp = @() foreach ($temp in $t.CurrentTemperature) { $currentTempKelvin = $temp / 10

ltpstress.sh-场景设置

由 不打扰是莪最后的温柔 提交于 2020-05-02 12:04:54
我们常用用LTP的ltpstress.sh脚本测试Linux的稳定性，以下将探讨一下如何好的进行Linux压力测试。 一.如何对内核进行压力测试？ 在进行压力测试之前，我们先思考一下压力测试要达到那些要求，才能说明Linux的稳定性。既然是压力测试，那么必然是超负荷测试，因此一般我们会对CPU、内存等使用率要求80%以上；另一个测试覆盖度。LTP已经为我们提供了测试用例，因此我们不用去考虑测试的覆盖度，那么我们关注的就是如何设置CPU和内存的压力。 二.ltpstress.sh默认测试场景 通常我们在进行Linux压力测试时，CPU和内存使用率要求90%以上，那么关键是如何设置ltpstress.sh才能满足这两个要求。如果我们在不修改ltpstress.sh直接进行压力测试时，CPU使用率一般会是90%左右，内存会是60%左右，但也不是绝对的。不过怎么说，这个可能不能满足我们的场景要求。我们首先分析一下ltpstress.sh如何设置cpu和内存压力的。ltpstress.sh是用genload进行压力设置，genload的具体用法可以ltp/testcase/bin/genload --help查看。 假设你的内存大小通过'free -m'看到为memSize=7834M,swapSize=2048,ltpstress.sh默认分配压力内存大小为stress_mem
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