What is IPC (in CPU)?

[DazzlingWhisker]

Hi everyone,

Could someone plz give me a good explenation on what CPU IPC is?

[Encrypt]

PC (Instructions per cycle) refers to the number of calculations a CPU can perform per clock cycle. If two CPUs have the same IPC they will have the same performance at the same frequency. For the practical purpose of comparing performance between different CPU architectures a workload that represents “typical use” is tested on both CPUs at the same clock speed to produce an IPC figure per core. IPC is measured under multi-core workloads to ensure that the resulting figures reflect total processing throughput. When the relative IPC between architectures is known, it simplifies comparisons between them.

Credit: Here

 

[DazzlingWhisker]

2 minutes ago, Encrypt said:

PC (Instructions per cycle) refers to the number of calculations a CPU can perform per clock cycle. If two CPUs have the same IPC they will have the same performance at the same frequency. For the practical purpose of comparing performance between different CPU architectures a workload that represents “typical use” is tested on both CPUs at the same clock speed to produce an IPC figure per core. IPC is measured under multi-core workloads to ensure that the resulting figures reflect total processing throughput. When the relative IPC between architectures is known, it simplifies comparisons between them.

Credit: Here

 

Awesome, thx

[minibois]

There are three major things that decide a CPUs performance:

Core count, frequency and IPC.

 

To put it very simply: IPC (instruction per cycle) is the amount of actions a CPU can do per 'Hz' (which is the cycle). Combine this with the (nowadays) GHz speeds of CPUs and all its cores/threads and you know how much 'stuff' a CPU can do in whatever timeframe.

 

IPC isn't always at in stone with all use cases, as some program libraries might make use of specific CPU architecture features.

[STRMfrmXMN]

Instructions per clock cycle. This is why an i5 6600K at 5 GHz is more powerful than an AMD FX8350 at 5GHz: the amount of processing power each MHz on each CPU can achieve is drastically different despite the FX's more cores.

[DazzlingWhisker]

Do anyone know a video (around 10 min or less) where someone compare IPC of 2 CPU?

[X_X]

IPC is dependent on opcodes so is dependent on software optimization and therefore one piece of software may show greater gains than another on the same system.

 

See http://www.agner.org/optimize/instruction_tables.pdf