Plan 9 /sys/man/2/worker

NAME

report, reportdata, reporting, reportcheck — print debugging/monitoring information

SYNOPSIS

#include <u.h> #include <libc.h> #include <thread.h> #include <worker.h> #include <error.h> #define report if(!Reporting){}else _report #define reportcheck(x) (Reporting?_reportcheck(x):0) #define reportdata if(!Reporting){}else _reportdata struct Request { void (*func)(Worker*, void*); void *arg; }; struct Worker { char name[64]; Request *r; /* Pointer to work to do */ ulong version; /* Incremented when accepting new work */ Channel *chan;/* for allocating work */ Channel *event; /* for signalling worker */ void *arg; /* set to func's arg */ void *aux; /* unused by library */ }; void workerdispatch(void (*f)(Worker*,void*), void *arg) Timer* timerdispatch(void (*f)(Worker*, void*), void *arg, vlong when) int timerrecall(Timer*) int recvt(Channel *c, void **v, vlong when) int sendt(Channel *c, void *v, vlong when)

DESCRIPTION

Typical Plan 9 servers create threads to handle incoming requests. The worker library allows these threads to be recycled so they can be reused for a next request.
Workerdispatch finds a waiting worker thread, or creates one if there are none and causes the thread to execute the function f in that thread. This function is called with two arguments, a pointer to the Worker structure and the argument arg provided by the caller of workerdispatch.
When the function returns, the worker thread makes itself available for the next request. Up to Nworker worker threads can be queued.
Timerdispatch calls workerdispatch in the future, at time when, which is given in nanoseconds (see nsec(2)). If when is in the past, the function is called immediately. It returns an address for use in timerrecall .
Timerrecall finds an outstanding timerdispatch event by the address returned by timerdisplatch and attempts to cancel it. If cancellation succeeds, it returns 1; if there is a race condition, or the function has already been called, it returns 0.
recvt and sendt execute send and receive operations with timeouts. The calls return 1 if the operation succeeded normally, 0 if it timed out and –1 if it was interrupted.

FILES

/sys/lib/acid/worker useful acid(1) functions for debugging worker programs.

SOURCE

/sys/src/libworker

SEE ALSO

thread(2) error(2) nsec(2)

DIAGNOSTICS

Uncaught errors (see error(2)) in the function f cause the function to be exited and the worker thread to requeue itself.

BUGS

The Stack for worker threads is only Wstack bytes


	report, reportdata, reporting, reportcheck — print debugging/monitoring information


	`/sys/lib/acid/worker` useful acid(1) functions for debugging worker programs.


	Uncaught errors (see error(2)) in the function f cause the function to be exited and the worker thread to requeue itself.


	Sape Mullender