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getrusage — Zeigt den aktuellen Ressourcenverbrauch an
Dies ist eine Schnittstlle zu getrusage(2). Stellt ein assoziatives Array mit den Daten zur Verfügung, die der Systemaufruf ausgibt. Wenn who 1 ist, wird getusage mit RUSAGE_CHILDREN aufgerufen.
Alle Einträge können über ihre Dukumentenfeldernamen aufgerufen werden.
Beispiel #1 getrusage() Beispiel
$dat = getrusage();
echo $dat["ru_nswap"]; # number of swaps
echo $dat["ru_majflt"]; # number of page faults
echo $dat["ru_utime.tv_sec"]; # user time used (seconds)
echo $dat["ru_utime.tv_usec"]; # user time used (microseconds)
getrusage() reports kernel counters that are updated only once application loses context and a switch to kernel space happens. For example on modern Linux server kernels that would mean that getrusage() calls would return information rounded at 10ms, desktop kernels - at 1ms.
getrusage() isn't usable for micro-measurements at all - and getmicrotime(true) might be much more valuable resource.
The author of the article mentioned in the previous post says "Once I got a negative value for both times - I have absolutely no clue how that can happen.". This is because time in microseconds is not padded with zeros from the left, therefore, you cannot concatenate the two numbers. Instead, you should normalize the values and then add them up:
$dat["ru_utime.tv_sec"]*1e6+$dat["ru_utime.tv_usec"];
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