Performance Bottlenecks in RHEL ?

[Chetan_Tiwary_]

What tool do you use to diagnose and resolve performance bottlenecks in RHEL ?

[Gopinath_Pigili]

Hello,

Best Practices for Performance Tuning in RHELRegular Monitoring: Continuously monitor system performance to track changes and identify new bottlenecks. Use tools like top, htop, and iostat.

In addtion to that, you can use AI-driven tools to track key metrics, monitor application behavior, trace errors and exceptions, understand the factors impacting your application in real time, and ensure your application is always running at peak efficiency.

It helps to proactively identify bottlenecks, resource constraints, and potential failures, ensuring seamless application performance, reduced downtime, and a smooth user experience.

Thanks

Gopinath

[mcapileibm]

I use top, htop, vmstat, iostat, sar, and perf to diagnose CPU, memory, and disk performance bottlenecks in RHEL.

[MonazahAzhar]

I use top , htop and vmstat mostly to deal such situation.

[Psehgaf]

Check System-Wide Performance

top: Overview of CPU, memory, and load.
htop: Interactive, detailed process monitoring.
vmstat: Reports CPU, memory, and I/O statistics.
sar: (sysstat package) – Historical performance metric

Check High CPU Usage

mpstat (sysstat package):Shows CPU usage per core.
pidstat: CPU usage per process.
perf: Detailed performance profiling.

[Manlio]

top / htop:
Provides a dynamic, real-time view of system processes and resource usage (CPU, memory, swap).
Helps identify processes consuming excessive resources.1
htop is an interactive improvement over top.
vmstat:
Reports virtual memory statistics, including CPU, memory, I/O, and system activity.2
Useful for identifying memory pressure and I/O bottlenecks.3
iostat:
Provides detailed I/O statistics for disk devices.4
Helps identify disk I/O bottlenecks and assess disk performance.5
mpstat:
Reports CPU utilization statistics for individual processors.6
Helps identify CPU bottlenecks and assess CPU load distribution.7
free:
Displays the amount of free and used memory in the system.
Helps identify memory pressure and swap usage.
sar (System Activity Reporter):
Collects and reports system activity data over time.
Useful for historical analysis and identifying trends.
It records the data that the other tools show in real time.
dstat:
A versatile resource monitoring tool that combines vmstat, iostat, mpstat, and netstat output.
Provides a comprehensive overview of system performance in a single output.

netstat / ss:
Displays network connections, routing tables, and network interface statistics.
Helps identify network bottlenecks and assess network performance.8
ss is a newer and more efficient replacement for netstat.
tcpdump / wireshark:
Captures network traffic for detailed analysis.
Helps identify network latency and packet loss.9
wireshark is a gui version of tcpdump.
iftop:
Displays real-time bandwidth usage on network interfaces.
Helps identify network bandwidth bottlenecks.

strace:
Traces system calls and signals made by a process.
Helps identify system call bottlenecks and debug application issues.
lsof (List Open Files):
Lists open files and the processes that are using them.
Helps identify processes holding onto resources and diagnose file descriptor leaks.
perf:
A powerful performance analysis tool that can profile CPU performance and identify hotspots in code.
Very usefull for developers.
gdb (GNU Debugger):
A debugger that allows you to examine the state of a running program.
Very usefull for developers.

blktrace:
Traces block device I/O operations.
Helps identify disk I/O bottlenecks and assess disk performance.

systemd-journald / journalctl:
Collects and manages system logs.
Helps identify system errors and warnings.
auditd / ausearch:
Audits system events and logs security-related information.
Helps identify security vulnerabilities and track system activity.

[fefe19]

Tools for Diagnosing and Resolving Performance Bottlenecks in RHEL

CPU Performance

top / htop – Shows real-time CPU usage per process

mpstat (from sysstat package) – Displays CPU usage across cores

pidstat – Monitors CPU usage per process over time

perf – Provides in-depth CPU performance profiling

Memory Usage

free -m – Displays memory usage and swap utilization

vmstat – Reports memory, CPU, and I/O statistics

sar -r – Collects and reports memory statistics over time

smem – Analyzes memory usage per process

Disk I/O Performance

iostat – Reports disk I/O utilization and latency

iotop – Displays real-time disk usage per process

blktrace / blkstat – Provides detailed block I/O tracing

df -h / du -sh – Checks disk space usage

Network Performance

netstat -s / ss – Displays active network connections and statistics

iftop – Monitors real-time network bandwidth usage

ip -s link – Displays network interface statistics

nload – Provides a graphical real-time network traffic overview

System-Wide Performance Monitoring

dstat – Combines CPU, disk, network, and memory stats in real-time

sar (from sysstat package) – Collects historical performance data

strace – Traces system calls of a process to detect slow operations

lsof – Lists open files to find processes causing resource contention

tuned-adm – Optimizes system performance based on predefined profiles

[uconn-alf02013]

Hi, in RHEL9 i have really learned to rely on "systemd-cgtop" to show me the realtime usage of resources when i triage bottlenecks. Sometimes limits.conf file needs tweaking also.

free -m  helps with servers using swap and need more.

lsof is nice too when things aren't working and you need to find what is the "hold up".....
EDIT:  Lastly strace when i am still scratching my head to figure out what is wrong.

Thank you.

[lintang404]

I usually identify performance issues in RHEL use various tools to help pinpoint the cause:

• CPU & Memory Usage: Use top or htop to monitor resource-heavy processes.
• Disk Performance: Use iostat or sarto collect disk activity and performance.
• Network Traffic: Use iftop to observe network usage in real-time.
• Process Behavior: Use strace to analyze how processes interact with the system.

For a broad system overview, dstat provides a combined view of CPU, memory, disk, and network performance.

[abhidd]

atop also one of the good tool

[afordona]

top: Provides a real-time view of system resource usage, including CPU, memory, and running processes.
iostat: Displays CPU load and disk I/O statistics.
vmstat: Reports on processes, memory, paging, block I/O, and CPU activity.
free: Checks memory usage.
netstat: Shows network statistics.
iotop: Monitors disk I/O usage by processes.
sar: Collects, reports, and saves system activity information, covering CPU, memory, I/O devices, network, and more