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perfmonctl (2)

PERFMONCTL(2) Linux System Calls PERFMONCTL(2) NAME perfmonctl - interface to PMU SYNOPSIS #include <syscall.h> #include <perfmon.h> long perfmonctl(int fd, int cmd, void *arg, int narg); DESCRIPTION perfmonctl system call provides an interface to PMU (performance moni- toring unit). PMU consists of PMD (performance monitoring data) regis- ters and PMC (performance monitoring control) registers, where are gathered the hardware statistic. perfmonctl will apply a function cmd to input arguments arg. The num- ber of arguments is defined by input variable narg. fd specifies the perfmon context to operate on. The implemented commands cmd are: PFM_CREATE_CONTEXT set up a context perfmonctl(int fd, PFM_CREATE_CONTEXT , pfarg_context_t *ctxt, 1); The fd parameter is ignored. A new context is created as speci- fied in ctxt and its file descriptor is returned in ctxt->ctx_fd. The file descriptor, apart from passing it to perfmonctl, can be used to read event notifications (type pfm_msg_t) using the read(2) system call. Both select(2) and poll(2) can be used to wait for event notifications. The context can be destroyed using the close(2) system call. PFM_WRITE_PMCS set PMC registers perfmonctl(int fd, PFM_WRITE_PMCS , pfarg_pmc_t *pmcs, n); PFM_WRITE_PMDS set PMD registers perfmonctl(int fd, PFM_WRITE_PMDS , pfarg_pmd_t *pmds, n); PFM_READ_PMDS read PMD registers perfmonctl(int fd, PFM_READ_PMDS , pfarg_pmd_t *pmds, n); PFM_START start monitoring perfmonctl(int fd, PFM_START , arg , 1); perfmonctl(int fd, PFM_START , NULL , 0); PFM_STOP stop monitoring perfmonctl(int fd, PFM_START , NULL , 0); PFM_LOAD_CONTEXT attach the context to a thread perfmonctl(int fd, PFM_LOAD_CONTEXT ,pfarg_load_t *largs,1); PFM_UNLOAD_CONTEXT detach the context from a thread perfmonctl(int fd, PFM_UNLOAD_CONTEXT , NULL , 0); PFM_RESTART restart monitoring after recieving an overflow notification perfmonctl(int fd, PFM_RESTART , NULL , 0); PFM_CREATE_EVTSETS create or modify event sets perfmonctl(int fd, PFM_CREATE_EVTSETS, pfarg_setdesc_t *desc , n); PFM_DELETE_EVTSETS delete event sets perfmonctl(int fd, PFM_DELETE_EVTSET, pfarg_setdesc_t *desc , n); PFM_GETINFO_EVTSETS get information about event sets perfmonctl(int fd, PFM_GETINFO_EVTSETS, pfarg_setinfo_t *info, n); RETURN VALUE performctl returns zero when the operation is successful. On error -1 is returned and an error code is set in errno. AVAILABILITY This syscall is implemented only on the IA-64 architecture since kernel 2.6. SEE ALSO gprof(1), The perfmon2 interface specification Linux 28 August 2006 PERFMONCTL(2)