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96 lines
2.3 KiB
96 lines
2.3 KiB
4 months ago
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.TH hardirqs 8 "2015-10-20" "USER COMMANDS"
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.SH NAME
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hardirqs \- Measure hard IRQ (hard interrupt) event time. Uses Linux eBPF/bcc.
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.SH SYNOPSIS
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.B hardirqs [\-h] [\-T] [\-N] [\-C] [\-d] [interval] [outputs]
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.SH DESCRIPTION
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This summarizes the time spent servicing hard IRQs (hard interrupts), and can
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show this time as either totals or histogram distributions. A system-wide
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summary of this time is shown by the %irq column of mpstat(1), and event
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counts (but not times) are shown by /proc/interrupts.
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WARNING: This currently uses dynamic tracing of hard interrupts. You should
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understand what this means before use. Try in a test environment. Future
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versions should switch to tracepoints.
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Since this uses BPF, only the root user can use this tool.
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.SH REQUIREMENTS
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CONFIG_BPF and bcc.
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.SH OPTIONS
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.TP
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\-h
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Print usage message.
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.TP
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\-T
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Include timestamps on output.
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.TP
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\-N
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Output in nanoseconds.
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.TP
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\-C
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Count events only.
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.TP
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\-d
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Show IRQ time distribution as histograms.
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.SH EXAMPLES
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.TP
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Sum hard IRQ event time until Ctrl-C:
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#
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.B hardirqs
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.TP
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Show hard IRQ event time as histograms:
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#
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.B hardirqs \-d
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.TP
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Print 1 second summaries, 10 times:
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#
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.B hardirqs 1 10
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.TP
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1 second summaries, printed in nanoseconds, with timestamps:
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#
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.B hardirqs \-NT 1
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.SH FIELDS
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.TP
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HARDIRQ
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The irq action name for this hard IRQ.
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.TP
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TOTAL_usecs
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Total time spent in this hard IRQ in microseconds.
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.TP
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TOTAL_nsecs
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Total time spent in this hard IRQ in nanoseconds.
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.TP
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usecs
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Range of microseconds for this bucket.
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.TP
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nsecs
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Range of nanoseconds for this bucket.
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.TP
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count
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Number of hard IRQs in this time range.
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.TP
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distribution
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ASCII representation of the distribution (the count column).
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.SH OVERHEAD
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This traces kernel functions and maintains in-kernel counts, which
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are asynchronously copied to user-space. While the rate of interrupts
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be very high (>1M/sec), this is a relatively efficient way to trace these
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events, and so the overhead is expected to be small for normal workloads, but
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could become noticeable for heavy workloads. Measure in a test environment
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before use.
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.SH SOURCE
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This is from bcc.
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.IP
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https://github.com/iovisor/bcc
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.PP
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Also look in the bcc distribution for a companion _examples.txt file containing
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example usage, output, and commentary for this tool.
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.SH OS
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Linux
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.SH STABILITY
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Unstable - in development.
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.SH AUTHOR
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Brendan Gregg
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.SH SEE ALSO
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softirqs(8)
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