Difference between revisions of "ALUSaturation"

From HPC Wiki
Jump to navigation Jump to search
m
 
Line 1: Line 1:
 +
[[Category:Performance Pattern]]
 
== Description ==
 
== Description ==
 
The pattern "ALU saturation" describes the performance limitation caused by fully utilizing a functional unit inside a CPU core.
 
The pattern "ALU saturation" describes the performance limitation caused by fully utilizing a functional unit inside a CPU core.

Latest revision as of 15:13, 3 September 2019

Description

The pattern "ALU saturation" describes the performance limitation caused by fully utilizing a functional unit inside a CPU core.

Symptoms

  • Throughput at design limit(s)
  • Good (low) CPI
  • Integral ratio of cycles to specific instruction count(s).

Detection

Use a hardware-counter tool like:

  • LIKWID with performance groups FLOPS_SP, FLOPS_DP, DATA and CLOCK
  • Same information can be provided by perf or PAPI

Possible optimizations and/or fixes