09-24-2010
Query on Running Multiple processes in background
HI All ,
Pardon me for asking some very basic questions,
I would be grateful if someone can help.
I am trying to execute a shell script which runs multiple processes in background. It includes various operations like copying , DB operations etc etc.
Now problem is that the complete script execution is taking a long long time, While we have optimized the DB part , I am on the lookout for other culprits.
Iam executing the script on T5K server . When executing multiple processes in background concurrently ....
1) Are all the processes allocated to a single CPU or multiple CPU ?
2) Can there be a possibility that a lot of time is wasted in scheduling the processes ?
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times(2) System Calls Manual times(2)
NAME
times - get process and child process times
SYNOPSIS
DESCRIPTION
fills the structure pointed to by buffer with time-accounting information. The structure defined in is as follows:
struct tms {
clock_t tms_utime; /* user time */
clock_t tms_stime; /* system time */"
clock_t tms_cutime; /* user time, children */
clock_t tms_cstime; /* system time, children */
};
This information comes from the calling process and each of its terminated child processes for which it has executed a or The times are in
units of 1/seconds, where is processor dependent. The value of can be queried using the function (see sysconf(2)).
is the CPU time used while executing instructions in the user space of the calling process.
is the CPU time used by the system on behalf of the calling process.
is the sum of the and of the child processes.
is the sum of the and of the child processes.
RETURN VALUE
Upon successful completion, returns the elapsed real time, in units of 1/of a second, since an arbitrary point in the past (such as system
start-up time). This point does not change from one invocation of to another. If fails, (clock_t) -1 is returned and is set to indicate
the error.
Remarks
has a granularity of one tick. Processes which run less than one tick may not register any value.
ERRORS
fails if buffer points to an illegal address. The reliable detection of this error is implementation dependent.
WARNINGS
Not all CPU time expended by system processes on behalf of a user process is counted in the system CPU time for that process.
SEE ALSO
time(1), exec(2), fork(2), gettimeofday(2), sysconf(2), time(2), wait(2).
STANDARDS CONFORMANCE
times(2)