qrusage

fast getrusage() binding to return process resource usage

binding to the unix getrusage(2) system call. Returns the resource usage metrics tracked by the operating system for the current process, or for its completed child processes. Low overhead, runs over 3 million calls / second (node v8.9.4).

Summary

var getrusage = require('qrusage');
var children_usage = getrusage(getrusage.RUSAGE_CHILDREN);
var my_usage = getrusage();
// => { utime: 0.031567, stime: 0.003945, maxrss: 25836, idrss: 0, ixrss: 0, isrss: 0,
//      minflt: 2011, majflt: 0, nswap: 0, inblock: 0, oublock: 0, msgsnd: 0,
//      msgrcv: 0, nsignals: 0, nvcsw: 12, nivcsw: 0 }

Benchmark

qtimeit=0.21.0 node=8.9.4 v8=6.1.534.50 platform=linux kernel=4.14.0-rc5-amd64 up_threshold=false
arch=ia32 mhz=4512 cpuCount=8 cpu="Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz"
name                  speed         (stats)                                                         rate
getrusage           201,548 ops/sec (2 runs of 94.3k calls in 0.936 out of 0.974 sec, +/- 0.43%)     202 >
q.getrusage       3,218,110 ops/sec (2 runs of 1.59m calls in 0.991 out of 1.050 sec, +/- 0.19%)    3218 >>>>>>>>>>>>>>>>

Functions

getrusage( [who] )

return usage for the current process. If called as getrusage(getrusage.RUSAGE_CHILDREN) will return usage for all the waited-for child processes of this process.

Extras

getrusage.cputime( [who] )

returns the number of seconds of user + system cpu time used. Accepts the getrusage.RUSAGE_SELF or getrusage.RUSAGE_CHILDREN argument.

For historical reasons, this call is also available as getrusage_cpu.

getrusage.gettimeofday( ), getrusage.fptime( )

returns a floating-point microsecond precision timestamp. Same speed as but higher precision than Date.now(); much faster than process.hrtime(). Unlike the Unix system call, this one returns a floating point value and not a struct timeval.

Also available as fptime(), being a floating-point version of the time() system call.

getrusage.microtime( )

returns an integer microsecond precision timestamp. This is the same timestamp value as gettimeofday above, but without any decimal rounding issues.

getrusage.cpuUsage( [lastUsage] )

return an object with properties user and system contain the number of microseconds of cpu time that this process has used since starting, or, if the optional lastUsage object is passed in, since that last usage was read.

This call is the same as process.cpuUsage() that appeared in node-v6.1.0.

Analytics

A few functions help with analytics gathering.

getrusage.storeUsage( name [,usage] )

Remember the provided usage (else the current usage) and associate it with name. This usage may be referred to by name later in calls to deltaUsage and sumUsage.

getrusage.removeUsage( name )

Remove and return from the store the usage associated with name. This call deletes the named usage from the store, and is intended to help with cleanup.

getrusage.deltaUsage( oldUsage [,newUsage] )

return an rusage object with the increases in usage from oldUsage to newUsage. Without newUsage it compares to the current usage. The usage may be specified by name if already defined with storeUsage.

deltaUsage diffs all fields, so the usage may be annotated with other metrics. Fields that are present in only one usage object are retained unmodified. Subtracted fields must be numeric.

getrusage.sumUsage( usage1, usage2, ... )

return an rusage object with the usage totals from the given rusage objects. Useful to quickly get parent + child usage, or to total up deltas. The usage may be specified by name if defined with storeUsage.

sumUsage retains existing properties and property order, and can be used to copy objects (sum a single usage) or to sum up annotated metrics fields. Properties that are present in only one object are retained unmodified. Summed fields must be numeric.

Notes

Unlike the unix system call, qrusage returns floating-point utime and stime instead of struct timeval timeval objects, and qrusage drops the ru_ prefix from the field names.

The list of getrusage fields (from linux man-pages-3.44 getrusage(2)):

struct timeval ru_utime; /* user CPU time used */
struct timeval ru_stime; /* system CPU time used */
long   ru_maxrss;        /* maximum resident set size */
long   ru_ixrss;         /* integral shared memory size */
long   ru_idrss;         /* integral unshared data size */
long   ru_isrss;         /* integral unshared stack size */
long   ru_minflt;        /* page reclaims (soft page faults) */
long   ru_majflt;        /* page faults (hard page faults) */
long   ru_nswap;         /* swaps */
long   ru_inblock;       /* block input operations */
long   ru_oublock;       /* block output operations */
long   ru_msgsnd;        /* IPC messages sent */
long   ru_msgrcv;        /* IPC messages received */
long   ru_nsignals;      /* signals received */
long   ru_nvcsw;         /* voluntary context switches */
long   ru_nivcsw;        /* involuntary context switches */

Linux does not maintain many of these fields, and currently returns zeroes for:

ru_ixrss
ru_idrss
ru_isrss
ru_nswap
ru_msgsnd
ru_msgrcv
ru_nsignals

qrusage returns

var getrusage = require('qrusage');
var usage = getrusage();
// =>
// { utime: 0.031567,
//   stime: 0.003945,
//   maxrss: 25836,
//   idrss: 0,
//   ixrss: 0,
//   isrss: 0,
//   minflt: 2011,
//   majflt: 0,
//   nswap: 0,
//   inblock: 0,
//   oublock: 0,
//   msgsnd: 0,
//   msgrcv: 0,
//   nsignals: 0,
//   nvcsw: 12,
//   nivcsw: 0 }

Related Work

• getrusage - getrusage.usage, 200k/s
• qrusage - qrusage.getrusage, 3200k/s

Change Log

• 1.5.1 change to build under node-v12
• 1.5.0 new calls storeUsage, removeUsage, deltaUsage, sumUsage
• 1.4.2 upgrade nan for node-v10, fix _float16 check, add to ci
• 1.4.1 100% test coverage, readme edits
• 1.4.0 3x speedup to getrusage and cpuUsage with node v4 and higher
• 1.3.0 cpuUsage() call
• 1.2.0 use nan 2.x for v8 bindings (5% slower though)
• 1.1.0 cputime() alias of getrusage_cpu(), microtime()