objective-c - 每个 CPU 内核处于 C0 电源状态的时间

Question

任何帮助弄清楚如何做到这一点的帮助都会很棒:每个 CPU 内核在过去一秒内花费了多少时间在 C0 电源状态。

这是一个 mac 应用程序，因此需要 Objective-C、cocoa 和 c。

Answer 1

OS X 没有任何公开 CPU c 状态的 API。但是，您似乎可以使用英特尔 CPU 上的 MWAIT/MONITOR 指令来执行此操作。 Intel 在引用手册的第 14.4 节中提到您可以使用此技术跟踪 C 状态驻留:

Software should use CPUID to discover if a target processor supports the enumeration of MWAIT extensions. If CPUID.05H.ECX[Bit 0] = 1, the target processor supports MWAIT extensions and their enumeration (see Chapter 3, “Instruction Set Reference, A-M,” of Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 2A).

If CPUID.05H.ECX[Bit 1] = 1, the target processor supports using interrupts as break-events for MWAIT, even when interrupts are disabled. Use this feature to measure C-state residency as follows:

Software can write to bit 0 in the MWAIT Extensions register (ECX) when issuing an MWAIT to enter into a processor-specific C-state or sub C-state.

When a processor comes out of an inactive C-state or sub C-state, software can read a timestamp before an interrupt service routine (ISR) is potentially executed.

您可以在同一手册中找到有关 MWAIT 指令的更多信息。祝你好运!

Intel's Reference Manual