Table of Contents
Systems Performance Table of Contents
Return to Systems Performance Index, Systems Performance Glossary, Systems Performance, 2nd Edition, Performance Bibliography, Systems Performance, Performance DevOps, IT Bibliography, DevOps Bibliography
“ (SysPrfBGrg 2021)
Contents at a Glance
Detailed Contents
1. Introduction
- 1.2 Roles
- 1.3 Activities
- 1.4 Perspectives
- 1.5 Performance Is Challenging
- 1.5.1 Subjectivity
- 1.5.2 Complexity
- 1.5.4 Multiple Performance Issues
- 1.6 Latency
- 1.7 Observability
- 1.7.2 Profiling
- 1.7.3 Tracing
- 1.8 Experimentation
- 1.9 Cloud Computing
- 1.10 Methodologies
- 1.11 Case Studies
- 1.11.1 Slow Disks
- 1.11.2 Software Change
- 1.11.3 More Reading
- 1.12 References
2. Methodologies
- 2.1 Terminology
- 2.2 Models
- 2.2.1 System Under Test
- 2.2.2 Queueing System
- 2.3 Concepts
- 2.3.1 Latency
- 2.3.2 Time Scales
- 2.3.3 Trade-Offs
- 2.3.4 Tuning Efforts
- 2.3.5 Level of Appropriateness
- 2.3.7 Point-in-Time Recommendations
- 2.3.9 Scalability
- 2.3.10 Metrics
- 2.3.11 Utilization
- 2.3.12 Saturation
- 2.3.13 Profiling
- 2.3.14 Caching
- 2.3.15 Known-Unknowns
- 2.4 Perspectives
- 2.4.2 Workload Analysis
- 2.5 Methodology
- 2.5.1 Streetlight Anti-Method
- 2.5.4 Ad Hoc Checklist Method
- 2.5.5 Problem Statement
- 2.5.6 Scientific Method
- 2.5.7 Diagnosis Cycle
- 2.5.8 Tools Method
- 2.5.9 The USE Method
- 2.5.10 The RED Method
- 2.5.11 Workload Characterization
- 2.5.12 Drill-Down Analysis
- 2.5.13 Latency Analysis
- 2.5.14 Method R
- 2.5.16 Baseline Statistics
- 2.5.17 Static Performance Tuning
- 2.5.18 Cache Tuning
- 2.5.19 Micro-Benchmarking
- 2.5.20 Performance Mantras
- 2.6 Modeling
- 2.6.2 Visual Identification
- 2.7.1 Resource Limits
- 2.8 Statistics
- 2.8.1 Quantifying Performance Gains
- 2.8.2 Averages
- 2.8.4 Coefficient of Variation
- 2.8.5 Multimodal Distributions
- 2.8.6 Outliers
- 2.9 Monitoring
- 2.9.1 Time-Based Patterns
- 2.9.2 Monitoring Products
- 2.9.3 Summary-Since-Boot
- 2.10 Visualizations
- 2.10.1 Line Chart
- 2.10.2 Scatter Plots
- 2.10.3 Heat Maps
- 2.10.4 Timeline Charts
- 2.10.5 Surface Plot
- 2.10.6 Visualization Tools
- 2.11 Exercises
- 2.12 References
3. Operating Systems
- 3.1 Terminology
- 3.2 Background
- 3.2.1 Kernel
- 3.2.3 System Calls
- 3.2.4 Interrupts
- 3.2.6 Processes
- 3.2.7 Stacks
- 3.2.8 Virtual Memory
- 3.2.9 Schedulers
- 3.2.10 File Systems
- 3.2.11 Caching
- 3.2.12 Networking
- 3.2.13 Device Drivers
- 3.2.14 Multiprocessor
- 3.2.15 Preemption
- 3.2.16 Resource Management
- 3.2.17 Observability
- 3.3 Kernels
- 3.3.1 Unix
- 3.3.2 BSD
- 3.3.3 Solaris
- 3.4 Linux
- 3.4.1 Linux Kernel Developments
- 3.4.2 systemd
- 3.4.4 Extended BPF
- 3.5 Other Topics
- 3.5.2 Unikernels
- 3.5.3 Microkernels and Hybrid Kernels
- 3.5.4 Distributed Operating Systems
- 3.6 Kernel Comparisons
- 3.7 Exercises
- 3.8 References
- 3.8.1 Additional Reading
4. Observability Tools
- 4.1 Tool Coverage
- 4.1.1 Static Performance Tools
- 4.1.2 Crisis Tools
- 4.2 Tool Types
- 4.2.1 Fixed Counters
- 4.2.2 Profiling
- 4.2.3 Tracing
- 4.2.4 Monitoring
- 4.3 Observability Sources
- 4.3.1 /proc
- 4.3.2 /sys
- 4.3.3 Delay Accounting
- 4.3.4 netlink
- 4.3.5 Tracepoints
- 4.3.6 kprobes
- 4.3.7 uprobes
- 4.3.8 USDT
- 4.3.9 Hardware Counters (PMCs)
- 4.3.10 Other Observability Sources
- 4.4 sar
- 4.4.2 sar(1) Monitoring
- 4.4.4 sar(1) Documentation
- 4.5 Tracing Tools
- 4.7 Exercises
- 4.8 References
5. Applications
- 5.1 Application Basics
- 5.1.1 Objectives
- 5.1.2 Optimize the Common Case
- 5.1.3 Observability
- 5.1.4 big O Notation
- 5.2.1 Selecting an I/O Size
- 5.2.2 Caching
- 5.2.3 Buffering
- 5.2.4 Polling
- 5.2.6 Non-Blocking I/O
- 5.2.7 Processor Binding
- 5.2.8 Performance Mantras
- 5.3 Programming Languages
- 5.3.1 Compiled Languages
- 5.3.2 Interpreted Languages
- 5.3.3 Virtual Machines
- 5.3.4 Garbage Collection
- 5.4 Methodology
- 5.4.1 CPU Profiling
- 5.4.2 Off-CPU Analysis
- 5.4.3 Syscall Analysis
- 5.4.4 USE Method
- 5.4.5 Thread State Analysis
- 5.4.6 Lock Analysis
- 5.4.8 Distributed Tracing
- 5.5 Observability Tools
- 5.5.1 perf
- 5.5.2 profile
- 5.5.3 offcputime
- 5.5.4 strace
- 5.5.5 execsnoop
- 5.5.6 syscount
- 5.5.7 bpftrace
- 5.6 Gotchas
- 5.6.1 Missing Symbols
- 5.6.2 Missing Stacks
- 5.7 Exercises
- 5.8 References
6. CPUs
- 6.1 Terminology
- 6.2 Models
- 6.2.1 CPU Architecture
- 6.2.2 CPU Memory Caches
- 6.2.3 CPU Run Queues
- 6.3 Concepts
- 6.3.1 Clock Rate
- 6.3.2 Instructions
- 6.3.3 Instruction Pipeline
- 6.3.4 Instruction Width
- 6.3.5 Instruction Size
- 6.3.6 SMT
- 6.3.8 Utilization
- 6.3.9 User Time / Kernel Time
- 6.3.10 Saturation
- 6.3.11 Preemption
- 6.3.12 Priority Inversion
- 6.3.13 Multiprocess, Multithreading
- 6.3.14 Word Size
- 6.3.15 Compiler Optimization
- 6.4 Architecture
- 6.4.1 Hardware
- 6.4.2 Software
- 6.5 Methodology
- 6.5.1 Tools Method
- 6.5.2 USE Method
- 6.5.4 Profiling
- 6.5.5 Cycle Analysis
- 6.5.6 Performance Monitoring
- 6.5.8 Priority Tuning
- 6.5.9 Resource Controls
- 6.5.10 CPU Binding
- 6.5.11 Micro-Benchmarking
- 6.6 Observability Tools
- 6.6.1 uptime
- 6.6.2 vmstat
- 6.6.3 mpstat
- 6.6.4 sar
- 6.6.5 ps
- 6.6.6 top
- 6.6.7 pidstat
- 6.6.9 turbostat
- 6.6.10 showboost
- 6.6.11 pmcarch
- 6.6.12 tlbstat
- 6.6.13 perf
- 6.6.14 profile
- 6.6.15 cpudist
- 6.6.16 runqlat
- 6.6.17 runqlen
- 6.6.18 softirqs
- 6.6.19 hardirqs
- 6.6.20 bpftrace
- 6.6.21 Other Tools
- 6.7 Visualizations
- 6.7.1 Utilization Heat Map
- 6.7.2 Subsecond-Offset Heat Map
- 6.7.3 Flame Graphs
- 6.7.4 FlameScoped
- 6.8 Experimentation
- 6.8.1 Ad Hoc
- 6.8.2 SysBench
- 6.9 Tuning
- 6.9.1 Compiler Options
- 6.9.2 Scheduling Priority and Class
- 6.9.3 Scheduler Options
- 6.9.4 Scaling Governors
- 6.9.5 Power States
- 6.9.6 CPU Binding
- 6.9.8 Resource Controls
- 6.9.9 Security Boot Options
- 6.9.10 Processor Options (BIOS Tuning)
- 6.10 Exercises
- 6.11 References
7. Memory
7.1 Terminology
7.2 Concepts
7.2.1 Virtual Memory
7.2.2 Paging
7.2.3 Demand Paging
7.2.4 Overcommit
7.2.5 Process Swapping
7.2.6 File System Cache Usage
7.2.7 Utilization and Saturation
7.2.8 Allocators
7.2.9 Shared Memory
7.2.10 Working Set Size
7.2.11 Word Size
7.3 Architecture
7.3.1 Hardware
7.3.2 Software
7.3.3 Process Virtual Address Space
7.4 Methodology
7.4.1 Tools Method
7.4.2 USE Method
7.4.3 Characterizing Usage
7.4.4 Cycle Analysis
7.4.5 Performance Monitoring
7.4.6 Leak Detection
7.4.7 Static Performance Tuning
7.4.8 Resource Controls
7.4.9 Micro-Benchmarking
7.4.10 Memory Shrinking
7.5 Observability Tools
7.5.1 vmstat
7.5.2 PSI
7.5.3 swapon
7.5.4 sar
7.5.5 slabtop
7.5.6 numastat
7.5.7 ps
7.5.8 top
7.5.9 pmap
7.5.10 perf
7.5.11 drsnoop
7.5.12 wss
7.5.13 bpftrace
7.5.14 Other Tools
7.6 Tuning
7.6.1 Tunable Parameters
7.6.2 Multiple Page Sizes
7.6.3 Allocators
7.6.4 NUMA Binding
7.6.5 Resource Controls
7.7 Exercises
7.8 References
8. File Systems
8 Systems Performance File Systems
8.1 Terminology
8.2 Models
8.2.1 File System Interfaces
8.2.2 File System Cache
8.2.3 Second-Level Cache
8.3 Concepts
8.3.1 File System Latency
8.3.2 Caching
8.3.3 Random vs. Sequential I/O
8.3.4 Prefetch
8.3.5 Read-Ahead
8.3.6 Write-Back Caching
8.3.7 Synchronous Writes
8.3.8 Raw and Direct I/O
8.3.9 Non-Blocking I/O
8.3.10 Memory-Mapped Files
8.3.11 Metadata
8.3.12 Logical vs. Physical I/O
8.3.13 Operations Are Not Equal
8.3.14 Special File Systems
8.3.15 Access Timestamps
8.3.16 Capacity
8.4 Architecture
8.4.1 File System I/O Stack
8.4.2 VFS
8.4.3 File System Caches
8.4.4 File System Features
8.4.5 File System Types
8.5 Methodology
8.5.1 Disk Analysis
8.5.2 Latency Analysis
8.5.3 Workload Characterization
8.5.4 Performance Monitoring
8.5.5 Static Performance Tuning
8.5.6 Cache Tuning
8.5.7 Workload Separation
8.5.8 Micro-Benchmarking
8.6 Observability Tools
8.6.1 mount
8.6.2 free
8.6.3 top
8.6.4 vmstat
8.6.5 sar
8.6.6 slabtop
8.6.7 strace
8.6.8 fatrace
8.6.9 LatencyTOP
8.6.10 opensnoop
8.6.11 filetop
8.6.12 cachestat
8.6.13 ext4dist (xfs, zfs, btrfs, nfs)
8.6.14 ext4slower (xfs, zfs, btrfs, nfs)
8.6.15 bpftrace
8.6.17 Other Tools
8.6.18 Visualizations
8.7 Experimentation
8.7.1 Ad Hoc
8.7.2 Micro-Benchmark Tools
8.7.3 Cache Flushing
8.8 Tuning
8.8.1 Application Calls
8.8.2 ext4
8.8.3 ZFS
8.9 Exercises
8.10 References
9. Disks
9.1 Terminology
9.2 Models
9.2.2 Caching Disk
9.2.3 Controller
9.3 Concepts
9.3.1 Measuring Time
9.3.2 Time Scales
9.3.3 Caching
9.3.4 Random vs. Sequential I/O
9.3.5 Read/Write Ratio
9.3.6 I/O Size
9.3.8 Non-Data-Transfer Disk Commands
9.3.9 Utilization
9.3.10 Saturation
9.3.12 Synchronous vs. Asynchronous
9.3.13 Disk vs. Application I/O
9.4 Architecture
9.4.2 Interfaces
9.4.4 Operating System Disk I/O Stack
9.5 Methodology
9.5.1 Tools Method
9.5.2 USE Method
9.5.3 Performance Monitoring
9.5.4 Workload Characterization
9.5.5 Latency Analysis
9.5.6 Static Performance Tuning
9.5.7 Cache Tuning
9.5.8 Resource Controls
9.5.9 Micro-Benchmarking
9.5.10 Scaling
9.6 Observability Tools
9.6.1 iostat
9.6.2 sar
9.6.3 PSI
9.6.4 pidstat
9.6.5 perf
9.6.6 biolatency
9.6.7 biosnoop
9.6.8 iotop, biotop
9.6.9 biostacks
9.6.11 bpftrace
9.6.12 MegaCli
9.6.15 Other Tools
9.7 Visualizations
9.7.2 Latency Scatter Plots
9.7.5 Utilization Heat Maps
9.8 Experimentation
9.8.1 Ad Hoc
9.8.3 Micro-Benchmark Tools
9.8.5 ioping
9.8.6 fio
9.8.7 blkreplay
9.9 Tuning
9.9.1 Operating System Tunables
9.9.2 Disk Device Tunables
9.9.3 Disk Controller Tunables
9.10 Exercises
9.11 References
10. Networks
10 Systems Performance Network
10.1 Terminology
10.2 Models
10.2.1 Network Interface
10.2.2 Controller
10.2.3 Protocol Stack
10.3 Concepts
10.3.2 Protocols
10.3.3 Encapsulation
10.3.4 Packet Size
10.3.5 Latency
10.3.6 Buffering
10.3.7 Connection Backlog
10.3.8 Interface Negotiation
10.3.9 Congestion Avoidance
10.3.10 Utilization
10.3.11 Local Connections
10.4 Architecture
10.4.1 Protocols
10.4.2 Hardware
10.4.3 Software
10.5 Methodology
10.5.1 Tools Method
10.5.2 USE Method
10.5.3 Workload Characterization
10.5.4 Latency Analysis
10.5.5 Performance Monitoring
10.5.6 Packet Sniffing
10.5.7 TCP Analysis
10.5.8 Static Performance Tuning
10.5.9 Resource Controls
10.5.10 Micro-Benchmarking
10.6 Observability Tools
10.6.1 ss
10.6.2 ip
10.6.3 ifconfig
10.6.4 nstat
10.6.5 netstat
10.6.6 sar
10.6.7 nicstat
10.6.8 ethtool
10.6.9 tcplife
10.6.10 tcptop
10.6.11 tcpretrans
10.6.12 bpftrace
10.6.13 tcpdump
10.6.14 Wireshark
10.6.15 Other Tools
10.7 Experimentation
10.7.1 ping
10.7.2 traceroute
10.7.3 pathchar
10.7.4 iperf
10.7.5 netperf
10.7.6 tc
10.7.7 Other Tools
10.8 Tuning
10.8.1 System-Wide
10.8.3 Configuration
10.9 Exercises
10.10 References
11. Cloud Computing
11 Systems Performance Cloud Computing
11.1 Background
11.1.1 Instance Types
11.1.2 Scalable Architecture
11.1.3 Capacity Planning
11.1.4 Storage
11.1.5 Multitenancy
11.1.6 Orchestration (Kubernetes)
11.2.1 Implementation
11.2.2 Overhead
11.2.3 Resource Controls
11.2.4 Observability
11.3 OS Virtualization
11.3.1 Implementation
11.3.2 Overhead
11.3.3 Resource Controls
11.3.4 Observability
11.4 Lightweight Virtualization
11.4.1 Implementation
11.4.2 Overhead
11.4.3 Resource Controls
11.4.4 Observability
11.5 Other Types
11.6 Comparisons
11.7 Exercises
11.8 References
12. Benchmarking
12 Systems Performance Benchmarking
12.1 Background
12.1.1 Reasons
12.1.2 Effective Benchmarking
12.1.3 Benchmarking Failures
12.2 Benchmarking Types
12.2.1 Micro-Benchmarking
12.2.2 Simulation
12.2.3 Replay
12.2.4 Industry Standard]]s
12.3 Methodology
12.3.1 Passive Benchmarking
12.3.2 Active Benchmarking
12.3.3 CPU Profiling
12.3.4 USE Method
12.3.5 Workload Characterization
12.3.9 Statistical Analysis
12.3.10 Benchmarking Checklist
12.5 Exercises
12.6 References
13. perf
13.1 Subcommands Overview
13.2 One-Liners
13.6 Tracepoint Events
13.7.1 kprobes
13.7.2 uprobes
13.7.3 USDT
13.8.1 Options
13.9.1 Options
13.9.2 CPU Profiling
13.9.3 Stack Walking
13.10.1 TUI
13.10.2 STDIO
13.11.1 Flame Graphs
13.13 Other Commands
13.14 perf Documentation
13.15 References
14. Ftrace
14.1 Capabilities Overview
14.4.3 Options
14.5 Tracepoints
14.5.1 Filter
14.5.2 Trigger
14.6 kprobes
14.6.2 Arguments
14.6.3 Return Values
14.7 uprobes
14.7.2 Arguments and Return Values
14.8.2 Options
14.9 Ftrace hwlat
14.10.2 Fields
14.10.3 Modifiers
14.10.6 Stack Trace Keys
14.11.1 Subcommands Overview
14.11.4 trace-cmd function_graph
14.11.6 trace-cmd Documentation
14.13.1 Tool Coverage
14.13.5 Example
14.13.6 perf-tools vs. BCC/BPF
14.13.7 Documentation
14.14 Ftrace Documentation
14.15 References
15. BPF
15.1 BCC
15.1.1 Installation
15.1.2 Tool Coverage
15.1.5 One-Liners
15.1.8 Documentation
15.2 bpftrace
15.2.1 Installation
15.2.2 Tools
15.2.3 One-Liners
15.2.4 Programming
15.2.5 Reference
15.2.6 Documentation
15.3 References
16. Case Study
16 Systems Performance Case Study
16.1.1 Problem Statement
16.1.3 Statistics
16.1.4 Configuration
16.1.5 PMCs
16.1.7 Tracing
16.1.8 Conclusion
16.2 Additional Information
16.3 References
Appendix
Fair Use Sources
Performance: Systems performance, Systems performance bibliography, Systems Performance Outline: (Systems Performance Introduction, Systems Performance Methodologies, Systems Performance Operating Systems, Systems Performance Observability Tools, Systems Performance Applications, Systems Performance CPUs, Systems Performance Memory, Systems Performance File Systems, Systems Performance Disks, Systems Performance Network, Systems Performance Cloud Computing, Systems Performance Benchmarking, Systems Performance perf, Systems Performance Ftrace, Systems Performance BPF, Systems Performance Case Study), Accuracy, Algorithmic efficiency (Big O notation), Algorithm performance, Amdahl's Law, Android performance, Application performance engineering, Async programming, Bandwidth, Bandwidth utilization, bcc, Benchmark (SPECint and SPECfp), BPF, bpftrace, Performance bottleneck (“Hotspots”), Browser performance, C performance, C++ performance, C# performance, Cache hit, Cache performance, Capacity planning, Channel capacity, Clock rate, Clojure performance, Compiler performance (Just-in-time (JIT) compilation - Ahead-of-time compilation (AOT), Compile-time, Optimizing compiler), Compression ratio, Computer performance, Concurrency, Concurrent programming, Concurrent testing, Container performance, CPU cache, CPU cooling, CPU cycle, CPU overclocking (CPU boosting, CPU multiplier), CPU performance, CPU speed, CPU throttling (Dynamic frequency scaling - Dynamic voltage scaling - Automatic underclocking), CPU time, CPU load - CPU usage - CPU utilization, Cycles per second (Hz), CUDA (Nvidia), Data transmission time, Database performance (ACID-CAP theorem, Database sharding, Cassandra performance, Kafka performance, IBM Db2 performance, MongoDB performance, MySQL performance, Oracle Database performance, PostgreSQL performance, Spark performance, SQL Server performance), Disk I/O, Disk latency, Disk performance, Disk speed, Disk usage - Disk utilization, Distributed computing performance (Fallacies of distributed computing), DNS performance, Efficiency - Relative efficiency, Encryption performance, Energy efficiency, Environmental impact, Fast, Filesystem performance, Fortran performance, FPGA, Gbps, Global Interpreter Lock - GIL, Golang performance, GPU - GPGPU, GPU performance, Hardware performance, Hardware performance testing, Hardware stress test, Haskell performance, High availability (HA), Hit ratio, IOPS - I/O operations per second, IPC - Instructions per cycle, IPS - Instructions per second, Java performance (Java data structure performance - Java ArrayList is ALWAYS faster than LinkedList, Apache JMeter), JavaScript performance (V8 JavaScript engine performance, Node.js performance - Deno performance), JVM performance (GraalVM, HotSpot), Kubernetes performance, Kotlin performance, Lag (video games) (Frame rate - Frames per second (FPS)), Lagometer, Latency, Lazy evaluation, Linux performance, Load balancing, Load testing, Logging, macOS performance, Mainframe performance, Mbps, Memory footprint, Memory speed, Memory performance, Memory usage - Memory utilization, Micro-benchmark, Microsecond, Monitoring
Linux/UNIX commands for assessing system performance include:
- uptime the system reliability and load average
- top for an overall system view
- vmstat vmstat reports information about runnable or blocked processes, memory, paging, block I/O, traps, and CPU.
- htop interactive process viewer
- dstat, atop helps correlate all existing resource data for processes, memory, paging, block I/O, traps, and CPU activity.
- iftop interactive network traffic viewer per interface
- nethogs interactive network traffic viewer per process
- iotop interactive I/O viewer
- iostat for storage I/O statistics
- netstat for network statistics
- mpstat for CPU statistics
- tload load average graph for terminal
- xload load average graph for X
- /proc/loadavg text file containing load average
(Event monitoring - Event log analysis, Google Cloud's operations suite (formerly Stackdriver), htop, mpstat, macOS Activity Monitor, Nagios Core, Network monitoring, netstat-iproute2, proc filesystem (procfs)]] - ps (Unix), System monitor, sar (Unix) - systat (BSD), top - top (table of processes), vmstat), Moore’s law, Multicore - Multi-core processor, Multiprocessor, Multithreading, mutex, Network capacity, Network congestion, Network I/O, Network latency (Network delay, End-to-end delay, packet loss, ping - ping (networking utility) (Packet InterNet Groper) - traceroute - netsniff-ng, Round-trip delay (RTD) - Round-trip time (RTT)), Network performance, Network switch performance, Network usage - Network utilization, NIC performance, NVMe, NVMe performance, Observability, Operating system performance, Optimization (Donald Knuth: “Premature optimization is the root of all evil), Parallel processing, Parallel programming (Embarrassingly parallel), Perceived performance, Performance analysis (Profiling), Performance design, Performance engineer, Performance equation, Performance evaluation, Performance gains, Performance Mantras, Performance measurement (Quantifying performance, Performance metrics), Perfmon, Performance testing, Performance tuning, PowerShell performance, Power consumption - Performance per watt, Processing power, Processing speed, Productivity, Python performance (CPython performance, PyPy performance - PyPy JIT), Quality of service (QOS) performance, Refactoring, Reliability, Response time, Resource usage - Resource utilization, Router performance (Processing delay - Queuing delay), Ruby performance, Rust performance, Scala performance, Scalability, Scalability test, Server performance, Size and weight, Slow, Software performance, Software performance testing, Speed, Stress testing, SSD, SSD performance, Swift performance, Supercomputing, Tbps, Throughput, Time (Time units, Nanosecond, Millisecond, Frequency (rate), Startup time delay - Warm-up time, Execution time), TPU - Tensor processing unit, Tracing, Transistor count, TypeScript performance, Virtual memory performance (Thrashing), Volume testing, WebAssembly, Web framework performance, Web performance, Windows performance (Windows Performance Monitor). (navbar_performance)
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