.TH slabratetop 8 "2016-10-17" "USER COMMANDS" .SH NAME slabratetop \- Kernel SLAB/SLUB memory cache allocation rate top. Uses Linux BPF/bcc. .SH SYNOPSIS .B slabratetop [\-h] [\-C] [\-r MAXROWS] [interval] [count] .SH DESCRIPTION This is top for the the rate of kernel SLAB/SLUB memory allocations. It works by tracing kmem_cache_alloc() calls, a commonly used interface for kernel memory allocation (SLAB or SLUB). It summarizes the rate and total bytes allocated of these calls per interval: the activity. Compare this to slabtop(1), which shows the current static volume of the caches. This tool uses kernel dynamic tracing of the kmem_cache_alloc() function. Since this uses BPF, only the root user can use this tool. .SH REQUIREMENTS CONFIG_BPF and bcc. .SH OPTIONS .TP \-C Don't clear the screen. .TP \-r MAXROWS Maximum number of rows to print. Default is 20. .TP interval Interval between updates, seconds. .TP count Number of interval summaries. .SH EXAMPLES .TP Summarize active kernel SLAB/SLUB calls (kmem_cache_alloc()), showing the top 20 caches every second: # .B slabratetop .TP Don't clear the screen, and top 8 rows only: # .B slabratetop -Cr 8 .TP 5 second summaries, 10 times only: # .B slabratetop 5 10 .SH FIELDS .TP loadavg: The contents of /proc/loadavg .TP CACHE Kernel cache name. .TP ALLOCS Allocations (number of calls). .TP BYTES Total bytes allocated. .SH OVERHEAD If kmem_cache_alloc() is called at a high rate (eg, >100k/second) the overhead of this tool might begin to be measurable. The rate can be seen in the ALLOCS column of the output. .SH SOURCE This is from bcc. .IP https://github.com/iovisor/bcc .PP Also look in the bcc distribution for a companion _examples.txt file containing example usage, output, and commentary for this tool. .SH OS Linux .SH STABILITY Unstable - in development. .SH AUTHOR Brendan Gregg .SH SEE ALSO slabtop(1)