Lists information about software interrupts
/proc/softirqs provides a snapshot of the softirqs. Softirqs, or 'software interrupts', are a mechanism in
the Linux kernel used to handle certain kinds of work that can be deferred but are time-critical.
They are a type of bottom half, a term used to describe work that is scheduled to run as soon as possible but after the
current, top half (interrupt context) task is completed.
What /proc/softirqs Contains
/proc/softirqs file contains counters for each softirq type on each processor. Each line represents a different
type of softirq, such as 'HI', 'TIMER', 'NETRX', and 'NETTX'. The columns represent the processors in the system, and
the numbers show how many times each softirq has been triggered on each processor.
HI: 0 12445 2746 3876
TIMER: 101238 125245 123245 124676
NET_RX: 34567 45678 23456 34567
NET_TX: 23456 34567 45678 56789
Importance of /proc/softirqs
/proc/softirqs can be crucial when diagnosing system performance issues, particularly those related to
networking and I/O.
An unusually high count of softirqs might indicate a highly loaded system or a network issue. If you notice that one CPU core is handling the majority of the softirqs, it could be an indication of an imbalance in the distribution of work among the cores.
How to Use /proc/softirqs
The output will provide a snapshot of the softirq counters at that moment.
Typical Problems Diagnosed with /proc/softirqs
/proc/softirqs can help diagnose a variety of problems, including but not limited to:
High system load: If the system is experiencing a high load, the softirq counts can help identify if the load is due to a large number of interrupts.
Network issues: A high count in 'NETRX' or 'NETTX' could indicate a network issue, as these softirqs handle received and transmitted network packets, respectively.
CPU imbalance: If one CPU core is handling the majority of the softirqs, it could indicate an imbalance in the distribution of work among cores.
/proc/softirqs file provides valuable insight into the internal workings of the Linux kernel.