Resusage

Obtaining of virtual memory, RAM and CPU usage by the whole system or by single process.

Currently works on Linux and Windows.

FreeBSD support is partial - only system-wide memory information and per-process CPU usage can be retrieved now.

Generating documentation

Ddoc:

dub build --build=docs

Ddox:

dub build --build=ddox

Brief

// import module
import resusage.memory;

// or the whole package
import resusage;

// get system memory usage
SystemMemInfo sysMemInfo = systemMemInfo(); 

// access properties
sysMemInfo.totalRAM;
sysMemInfo.usedRAM;
sysMemInfo.freeRAM;

sysMemInfo.totalVirtMem;
sysMemInfo.usedVirtMem;
sysMemInfo.freeVirtMem;

// actualize values after some amount of time
sysMemInfo.update();

// get memory usage of the current process
ProcessMemInfo procMemInfo = processMemInfo();

// or pass process ID to get info about specific process
int pid = ...;
ProcessMemInfo procMemInfo = processMemInfo(pid);

// access properties
procMemInfo.usedVirtMem;
procMemInfo.usedRAM;

// actualize values after some amount of time
procMemInfo.update();

//import module
import resusage.cpu;

// create watcher to watch system CPU
auto cpuWatcher = new SystemCPUWatcher();

// get actual value when needed
double percent = cpuWatcher.current();

// create CPU watcher for current process
auto cpuWatcher = new ProcessCPUWatcher();

// or for process with given id
int pid = ...;
auto cpuWatcher = new ProcessCPUWatcher(pid);

// get actual value when needed
double percent = cpuWatcher.current();

Examples

Total usage

Prints total amount of virtual and physical memory (in bytes) and their current usage in the system (in percents).

dub examples/totalusage.d

Process usage

Prints amount of virtual and physical memory currently used by process, in bytes.

dub examples/processusage.d `pidof process`

CPU Watcher

All following examples show CPU time used by a system or by a process in the 0-100% range.

Watch system CPU time:

dub examples/cpuwatcher.d

Watch process CPU time:

dub examples/cpuwatcher.d `pidof process`

Spawn process and watch for its CPU time:

dub examples/cpuwatcher.d --spawn firefox

Adjust the rate of output:

dub examples/cpuwatcher.d --rate=1 --spawn firefox

CPU self watcher

Consume CPU time and report CPU usage by this process:

dub examples/cpuselfwatcher --threads=2

E.g. if you have 4 cores and run this example with 2 threads it will report 50% CPU time.

Platform notes and implementation details

Windows

In order to provide some functionality resusage dynamically loads the following libraries at startup:

1. Psapi.dll for GetProcessMemoryInfo.
2. Pdh.dll to calculate CPU time used by system.

If Psapi.dll or Pdh.dll could not be loaded, corresponding functions will always throw WindowsException.

Linux

Uses sysinfo, clock_gettime and proc stats.

FreeBSD

Uses sysctl to get RAM and libkvm to get swap memory to calculate virtual memory. Uses clock_gettime to evaluate CPU usage.