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Linux - System: Tune System Performance

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• Linux - System: Tune System Performance
  • Tune System Performance
  • Package tuned: Tuning by Profiles
    • Predefined Profiles
    • Command
  • Lab: Tune System Performance by tuned
    • List all profiles and check active profile
    • Swith current profile
    • Tune off and switch to recommended profile
    • Change profile via web console
  • Command nice and renice: Tuning by Priority of Processes
    • Niceness and Priority
    • Check Niceness of Running Processes
    • Command
  • Lab: Tuning by Prioritize Process

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Tune System Performance

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Package tuned: Tuning by Profiles

• tuned

  • a powerful tool designed for dynamic system performance tuning.
  • It optimizes system settings automatically based on predefined profiles tailored for different workloads and hardware configurations

• Package

rpm -qa | grep tuned
sudo yum install tuned

• Service
  • tuned daemon

sudo systemctl status tuned
sudo systemctl enable --now tuned

• CF dir

/etc/tuned

• Profile locate

• /usr/lib/tuned

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Predefined Profiles

• Predefined profiles
  • used for tuned service to automatically adjust sytem to get the best performance.

Profile	Description
balanced	Default profile balancing performance and power consumption.
throughput-performance	Optimized for high throughput workloads (e.g., databases, web servers).
latency-performance	Optimized for low latency workloads (e.g., real-time applications).
powersave	Minimizes power consumption, suitable for laptops or energy-efficient setups.
virtual-guest	Optimized for virtual machines running as guests.
virtual-host	Optimized for virtualization hosts managing VMs.
desktop	Optimized for desktop systems, improving responsiveness.
network-latency	Optimized for low-latency network environments.
network-throughput	Optimized for high-throughput network environments.
oracle	Optimized for Oracle database workloads.
hpc-compute	Optimized for high-performance computing (HPC) environments.

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Command

• tuned-adm: command-line interface, allowing administrators to apply, manage, and customize tuning profiles easily.

CMD	DESC
tuned-adm list	List Available Profiles
tuned-adm active	Show Current Active Profile
tuned-adm recommend	Recommend an Optimal Profile for the System
tuned-adm profile profile_name	Switch to a desired Profile
tuned-adm off	Turn Off Tuning

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Lab: Tune System Performance by tuned

List all profiles and check active profile

# Check Current Active Profile
tuned-adm active
# Current active profile: virtual-guest

# List Available Profiles
tuned-adm list
# Available profiles:
# - accelerator-performance     - Throughput performance based tuning with disabled higher latency STOP states
# - aws                         - Optimize for aws ec2 instances
# - balanced                    - General non-specialized tuned profile
# - desktop                     - Optimize for the desktop use-case
# - epyc-eda                    - Optimize for EDA compute workloads on AMD EPYC CPUs
# - hpc-compute                 - Optimize for HPC compute workloads
# - intel-sst                   - Configure for Intel Speed Select Base Frequency
# - latency-performance         - Optimize for deterministic performance at the cost of increased power consumption
# - network-latency             - Optimize for deterministic performance at the cost of increased power consumption, focused on low latency network performance
# - network-throughput          - Optimize for streaming network throughput, generally only necessary on older CPUs or 40G+ networks
# - optimize-serial-console     - Optimize for serial console use.
# - powersave                   - Optimize for low power consumption
# - throughput-performance      - Broadly applicable tuning that provides excellent performance across a variety of common server workloads
# - virtual-guest               - Optimize for running inside a virtual guest
# - virtual-host                - Optimize for running KVM guests
# Current active profile: virtual-guest

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Swith current profile

# switch to a profile
tuned-adm profile balanced
# confirm
tuned-adm active
# Current active profile: balanced

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Tune off and switch to recommended profile

# turn off tuned, means run system manually
tuned-adm off
# confirm, by checking the current profile
tuned-adm active
# No current active profile.

# get the recommended profile
tuned-adm recommend
# virtual-guest

# switch to recommended profile
tuned-adm profile virtual-guest
# confirm
tuned-adm active
# Current active profile: virtual-guest

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Change profile via web console

• https://ip:9090

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Command nice and renice: Tuning by Priority of Processes

• nice and renice commands

  • used to manage the priority of processes.
  • They influence how much CPU time a process gets relative to others by adjusting its “niceness” value.

• Package: GNU Coreutils package

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Niceness and Priority

• Niceness Value for a process:

  • Default : 0.
  • Highest niceness: 19
  • Higher niceness(e.g., 10, 19): Process runs with lower priority.
    • making it less CPU-intensive.
  • Lower niceness (e.g., -5, -20): Process runs with higher priority.
  • Lowest niceness: -20

• A higher niceness value means the process will take less CPU time, while a lower niceness value makes the process more CPU-intensive.

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• Priority for a process:
  • The kernel calculates the priority of a process based on its niceness value.
  • Actual priority = Niceness + Base priority (managed by the kernel).

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Check Niceness of Running Processes

• top command:

  • NI Column:
    • Nice Value
      • priority of the task
    • range from -20 to 19
    • adjust by nice command
  • PR column
    • Priority(priority of the task with the rt values)
    • range from -99 to 39

• ps command to get Nice Value

ps axo pid,comm,nice,cls --sort=-nice
#   PID COMMAND          NI CLS
#    50 khugepaged       19  TS
#    49 ksmd              5  TS
#   970 rtkit-daemon      1  TS
#     1 systemd           0  TS
#     2 kthreadd          0  TS
#     6 kworker/0:0-eve   0  TS
#    11 rcu_tasks_rude_   0  TS
#    12 rcu_tasks_trace   0  TS
#    13 ksoftirqd/0       0  TS
#    14 rcu_sched         0  TS
#    15 migration/0       -  FF
#    16 watchdog/0        -  FF
#    17 cpuhp/0           0  TS
#    18 cpuhp/1           0  TS
#    19 watchdog/1        -  FF
#    20 migration/1       -  FF
#    21 ksoftirqd/1       0  TS
#    24 cpuhp/2           0  TS
#    25 watchdog/2        -  FF
#    26 migration/2       -  FF

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Command

• renice command:
  • used to change the niceness value of an already running process.

CMD	DESC
nice process_name	Run a Command with Default Niceness (0)
nice -n 10 process_name	Run a Command with a Specific Niceness Value
renice -n 10 1234	Change the Niceness of a Process
renice 10 -p 1234	Change the Niceness of a Process
renice 5 -p 1234 5678	Change Niceness for Multiple Processes
renice 10 -u username	Change Niceness for All Processes of a User
renice 5 -g 123	Change Niceness for a Process Group

• Privileges:

  • Only the root user can:
    • Start a process with a negative niceness value using nice.
    • Decrease (raise the priority) of a process using renice.
  • Regular users can:
    • Increase the niceness value (lower the priority) of their own processes.

• Real-World Use Cases

  • Backup Jobs:
    • Run backups with higher niceness (e.g., nice -n 15) to prevent them from affecting other processes.
  • Critical Processes:
    • Assign lower niceness (e.g., nice -n -5) to ensure critical tasks like databases or web servers get sufficient CPU time.
  • Load Management:
    • Use renice to adjust priorities dynamically when system resources are under heavy load.

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Lab: Tuning by Prioritize Process

# sets the process niceness to 15, making it less CPU-intensive.
nice -n 15 tar -czf backup.tar.gz /data

# run top by default, NI is 0
top
#     PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
#   11759 root      20   0  264296   4532   3652 R   0.7   0.1   0:00.04 top

# Run a Command with High Priority, NI is -5
sudo nice -n -5 top
#     PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
#   11996 root      15  -5  264296   4656   3776 R   1.0   0.1   0:00.17 top

# adjust priority of a process
renice -n 15 11996
# top display:
#     PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
#   11996 root      35  15  264296   4656   3776 R   0.7   0.1   0:00.35 top

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