Manual: nodestat-bpfcc

ustat(8)				   System Manager's Manual				    ustat(8)

NAME
       ustat,  javastat,  nodestat,  perlstat,	phpstat, pythonstat, rubystat, tclstat - Activity stats from
       high-level languages.

SYNOPSIS
       javastat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       nodestat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       perlstat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       phpstat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       pythonstat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       rubystat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       tclstat [-C] [-S {cload,excp,gc,method,objnew,thread}] [-r MAXROWS] [-d] [interval [count]]
       ustat [-l {java,node,perl,php,python,ruby,tcl}] [-C]  [-S  {cload,excp,gc,method,objnew,thread}]	 [-r
       MAXROWS] [-d] [interval [count]]

DESCRIPTION
       This  is	 "top"	for high-level language events, such as garbage collections, exceptions, thread cre‐
       ations, object allocations, method calls, and more. The events are aggregated for  each	process	 and
       printed in a top-like table, which can be sorted by various fields. Not all language runtimes provide
       the same set of details.

       This uses in-kernel eBPF maps to store per process summaries for efficiency.

       This tool relies on USDT probes embedded in many high-level languages, such as Java, Node, Perl, PHP,
       Python,	Ruby, and Tcl. It requires a runtime instrumented with these probes, which in some cases re‐
       quires building from source with a USDT-specific flag, such as "--enable-dtrace" or  "--with-dtrace".
       For  Java,  some	 probes are not enabled by default, and can be turned on by running the Java process
       with  the  "-XX:+ExtendedDTraceProbes"  flag.   For   PHP   processes,	the   environment   variable
       USE_ZEND_DTRACE must be set to 1.

       Newly-created  processes	 will only be traced at the next interval. If you run this tool with a short
       interval (say, 1-5 seconds), this should be virtually unnoticeable. For longer intervals,  you  might
       miss processes that were started and terminated during the interval window.

       Since this uses BPF, only the root user can use this tool.

REQUIREMENTS
       CONFIG_BPF and bcc.

OPTIONS
       -l {java,node,perl,php,python,ruby,tcl}
	      The language to trace. By default, all languages are traced.

       -C     Do not clear the screen between updates.

       -S {cload,excp,gc,method,objnew,thread}
	      Sort the output by the specified field.

       -r MAXROWS
	      Do not print more than this number of rows.

       -d     Print the resulting BPF program, for debugging purposes.

       interval
	      Interval between updates, seconds.

       count  Number of interval summaries.

EXAMPLES
       Summarize activity in high-level languages, 1 second refresh:
	      # ustat

       Don't clear the screen, and top 8 rows only:
	      # ustat -Cr 8

       5 second summaries, 10 times only:
	      # ustat 5 10

FIELDS
       loadavg
	      The contents of /proc/loadavg

       PID    Process ID.

       CMDLINE
	      Process  command	line  (often  the  second and following arguments will give you a hint as to
	      which application is being run.

       METHOD/s
	      Count of method invocations during interval.

       GC/s   Count of garbage collections during interval.

       OBJNEW/s
	      Count of objects allocated during interval.

       CLOAD/s
	      Count of classes loaded during interval.

       EXC/s  Count of exceptions thrown during interval.

       THR/s  Count of threads created during interval.

OVERHEAD
       When using this tool with high-frequency events, such as method calls, a very  significant  slow-down
       can be expected. However, many of the high-level languages covered by this tool already have a fairly
       high per-method invocation cost, especially when running in interpreted mode. For the lower-frequency
       events,	such  as  garbage  collections	or thread creations, the overhead should not be significant.
       Specifically, when probing Java processes and not using	the  "-XX:+ExtendedDTraceProbes"  flag,	 the
       most expensive probes are not emitted, and the overhead should be acceptable.

SOURCE
       This is from bcc.

	      https://github.com/iovisor/bcc

       Also look in the bcc distribution for a companion _example.txt file containing example usage, output,
       and commentary for this tool.

OS
       Linux

STABILITY
       Unstable - in development.

AUTHOR
       Sasha Goldshtein

SEE ALSO
       trace(8), argdist(8), tplist(8)

USER COMMANDS					 2018-10-09					    ustat(8)