cpu

问题 I am currently working on a project in Android. I want to get the total cpu usage of each and every process. So i am using the contents of "/proc/pid/stat". I referred this answer to get the stats. Now i got all the utime, stime etc., The problem is with the value of "Hertz". The answer says that it is the number of clock ticks per second. I don't get the exact meaning of clock tick even after browsing a lot. What is a clock tick and is it the frequency of the processor? And the answer says

问题 For example, for a 8-bit CPU, the stack size is expected to be 8-bit wide, and 16-bit CPU vs 16-bit stack width, and 32-bit, 64-bit CPU, and so on. Is it true for all architectures? 回答1: A CPU has a data bus and a address bus. They can have the same width, but they often aren't. The stack pointer is a pointer to memory, so its often as wide as the address bus, unless there is some (weird/obscure) conversion used internally. The instruction pointer (points to the current instruction) is also a

问题 Since my pc's fan is very loud, I'd like to make myself a program to "shut it up" when it's not required to be running at full speed. I want to make it with python, so is there any module that can detect the temperature and/or set the fan speed? 回答1: You might be able to do it in WMI. There's a related question here. 回答2: Don't use python, or WMI. If you have Windows, and if you can't use speedfan, this is best done in the BIOS layer, with Microsoft's ASL Compiler. Using that, you can set

问题 In this case, say I wanted to wait on a condition to happen, that may happen at any random time. while True: if condition: #Do Whatever else: pass As you can see, pass will just happen until the condition is True. But while the condition isn't True the cpu is being pegged with pass causing higher cpu usage, when I simply just want it to wait until the condition occurs. How may I do this? 回答1: See Busy_loop#Busy-waiting_alternatives: Most operating systems and threading libraries provide a

问题 I have to put my device into a very deep low power mode from Linux 2.6.38 and therefore, it's necessary to suspend all components, including CPU und DDR2. What I found out so far is that I have to copy the core assembler function into the processor's internal memory and execute it from there. Basically, it looks like this: cpaddr = iram_alloc(SZ_1K, &iram_addr); if(!cpaddr) return -ENOMEM; suspend_iram_base = __arm_ioremap(iram_addr, SZ_1K, MT_HIGH_VECTORS); memcpy(suspend_iram_base, cpu_v6

问题 I follow this document and using perf record with --intr-regs=ax,bx,r15 , trying to log additional CPU register information with PEBS record. But how do I view those info from perf.data? The original command is perf report , and it only shows a few fields such as overhead, command, shared object and symbol. Is there any way to show CPU regs' value? 回答1: Try perf script data dumping command with the iregs field: perf script -F ip,sym,iregs . All fields -F are documented with source code of

问题 I follow this document and using perf record with --intr-regs=ax,bx,r15 , trying to log additional CPU register information with PEBS record. But how do I view those info from perf.data? The original command is perf report , and it only shows a few fields such as overhead, command, shared object and symbol. Is there any way to show CPU regs' value? 回答1: Try perf script data dumping command with the iregs field: perf script -F ip,sym,iregs . All fields -F are documented with source code of

问题 I am writing a boot load and try to test Inter-Processor Interrupt. I got the following 2 questions blocked me: 1, Where I can find the procedure of starting up APs; 2, When issuing IPI, where I should load the memory address to tell the target processor which memory address to start with. Thanks for answering, and if you could be so kind to attach a assembly example. 回答1: I lifted this from the now defunct Stackoverflow Documentation project. This was originally written by Margaret Bloom and

问题 Is there a function or any other way to know, programatically, what core of what processor a given thread of my program (pid) is running on? Both OpenMP or Pthreads solutions would help me, if possible. Thanks. 回答1: This is going to be platform-specific, I would think. On Windows you can use NtGetCurrentProcessorNumber, but this is caveat-ed as possibly disappearing. I expect this is hard to do, because there's nothing to stop the thread being moved to a new core at any time (in most apps,

问题 I'm looking for a way to occupy exactly 80% (or any other number) of a single CPU in a consistent manner. I need this for some unit test that tests a component that triggers under specific CPU utilization conditions For this purpose I can assume that the machine is otherwise idle. What's a robust and possibly OS independent way to do this? 回答1: There is no such thing as occupying the CPU 80% of the time. The CPU is always either being used, or idle. Over some period of time, you can get