Hardware Profiling Collector Bypassing Kernel Overhead
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Solution Overview
Problem
Conventional performance profilers in computer systems face inefficiencies due to kernel-level processing requirements, which slow down applications and increase cache perturbations, limiting the frequency of data samples collected and thus the accuracy of profiled data.
Innovation Solution
A profiling collector module is introduced that operates directly from the raw machine state, bypassing the need for kernel-level processing by utilizing a private bank of registers and redirecting interrupt vectors, allowing for more efficient sampling without the overhead of bridge and kernel processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional performance profilers operate at kernel level with bridge module processing, then system stability and access to performance data are ensured, but processing overhead increases and application performance deteriorates
Solution Approach 1:
The patent introduces a performance monitoring unit (PMU) as an intermediary component that operates independently of the kernel. The PMU captures performance data directly from processor events using dedicated hardware counters and status registers, eliminating the need for kernel-level bridge modules. This intermediary approach allows accurate performance measurement while keeping the application runtime kernel-free, thus resolving the contradiction between measurement precision and application productivity.
2Measurement precision
If sampling rate is increased to improve profiler accuracy, then measurement precision improves, but processing overhead and cache perturbations increase
Solution Approach 1:
The performance monitoring unit operates autonomously using processor-generated events and dedicated hardware counters. The PMU self-captures performance data directly from processor state without requiring external sampling interrupts or kernel intervention. This self-service mechanism enables high-accuracy performance measurement at minimal processing overhead, as the PMU utilizes existing processor resources and generates data passively through hardware event matching rather than active sampling.
3Reliability
If kernel-level processing is used for performance sampling, then access to system performance data is ensured, but sampling frequency is limited due to processing overhead
Solution Approach 1:
The patent replaces the software-based kernel-level sampling mechanism with a hardware-based performance monitoring unit. The PMU uses processor hardware counters, status registers, and event-matching logic to capture performance data directly at the hardware level. This substitution of hardware for software eliminates kernel processing overhead and enables high-frequency sampling while maintaining data reliability through dedicated performance monitoring circuitry that operates independently of the operating system.
Data Source
AI summary
In one embodiment a computer system comprises one or more processors and a memory module communicatively connected to the one or more processors. The memory module comprises logic instructions which, when executed on the one or more processors configure the one or more processors to receive an interrupt in an execution thread of a process executing at an application layer of an operating system, intercept the interrupt in a profiling collector module invoked directly from a raw machine state, execute a profiling collection process, and return control from the interrupt to the execution thread when the profiling collection process is complete.