The invention of OoOE helped engineers guarantee certain performance levels without relying entirely on developers to write perfect code. Modern x86 CPUs both re-order the instructions they receive and convert those x86 instructions into smaller, RISC-like micro-ops.
#How many computers use windows code#
The CPU executes the code the OS dispatches to it, but the OS doesn’t have anything to do with the actual execution of the instruction stream. These CPUs re-order the instructions they receive in real-time, for optimal execution. All modern high-performance CPU cores, including the “big” smartphone cores in big.Little, are OoOE designs. Modern CPUs, including the x86 chips built 20 years ago, implement what’s known as Out of Order Execution, or OoOE. In consumer systems, this means you have support for CPU core count * 2 threads, or 8C/16T, for example. These days, the majority of CPUs from both companies offer SMT. Both companies have historically deployed it strategically, offering it on some products but not on others. Currently, both AMD and Intel use SMT to boost CPU performance. Intel calls this Hyper-Threading Technology, AMD just calls it SMT. SMT = The CPU can execute more than one thread simultaneously, by scheduling a second thread that can use the execution units not currently in use by the first thread. Symmetric Multiprocessing and Symmetric Multithreading are two different things. Today, the terms multithreading and multiprocessing are often colloquially used to mean the same thing, but that wasn’t always the case. Important point: Everything we’ve discussed so far applies to single-core CPUs. The advent of caches meant that CPUs could keep small collections of instructions nearby for immediate number crunching, while multithreading ensured the CPU always had something to do. This became important in the 1980s, when CPU and RAM clocks began to separate, with memory speed and bandwidth both increasing much more slowly than CPU clock speed. The simplest form of multithreading is coarse-grained multithreading, in which the operating system switches to a different thread rather than sitting around waiting for the results of a calculation.
How do we improve computer performance?Īs computers got faster, developers created more sophisticated software. Each process requires at last one thread. Problem: CPUs can only execute one thread at a time. In this simplified factory analogy, the process is the entire procedure for manufacturing the product, while the thread is each individual task.
Processes are computer programs that are executed in one or more threads. One step above the thread, we have the process. If you wanted to make an analogy, you could compare a thread to a one step on an assembly line. The “unit” of work - the smallest block of work that is managed by the OS scheduler - is called a thread. The scheduler consists of whatever method is used by the OS to assign work to resources, like the CPU and GPU, that then complete that work. One of the critical components of the operating system is called the scheduler. Your CPU core count is one of the characteristics reported to both the UEFI and the operating system.
If the UEFI can’t identify your CPU properly, your motherboard typically won’t boot. Your CPU passes certain information about its own operating characteristics over to the motherboard UEFI, which then uses this information to initialize the motherboard and boot the system. When you turn on a PC, before the OS has even loaded, your CPU and motherboard “handshake”, for lack of a better term.
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