From db9c0df934e62835bc09604a7ae7932693b4254a Mon Sep 17 00:00:00 2001 From: Paul Jakma Date: Sun, 27 Aug 2006 06:44:02 +0000 Subject: [lib] Bug #134: threads should be more robust against backward time jumps 2006-08-25 Paul Jakma * thread.c: (general) Add support for monotonic clock, it may still jump forward by huge amounts, but should be immune to going backwards. Fixes bug #134. (quagga_gettimeofday_relative_adjust) helper, does what name says - adjusts gettimeofday based relative timer. (quagga_gettimeofday) helper to keep recent_time up to date. (quagga_get_relative) helper, update and getch the relative timer using gettimeofday(). POSIX CLOCK_MONOTONIC is also supported, but the code is not enabled yet nor tested. (quagga_real_stabilised) helper, retrieve absolute time but stabilised so as to never decrease. (quagga_gettime) Exported interface, analogous to POSIX clock_gettime() in interface, supporting several clocks. (quagga_time) Exported interface, analogous to traditional time(), will never decrease. (recent_relative_time) Convenience function to retrieve relative_time timeval, similar to existing recent_time absolute timeval, for when an approximately recent value will do. (remainder) Update to use above helpers. (thread_getrusage) Previously was a macro, but needs to be a function to twiddle with thread.c private stuff. * thread.c: Point the GETRUSAGE macro at previous function. Export quagga_gettime, quagga_time and recent_relative_time for general use. --- lib/thread.h | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'lib/thread.h') diff --git a/lib/thread.h b/lib/thread.h index 0670a890..1c324d86 100644 --- a/lib/thread.h +++ b/lib/thread.h @@ -31,14 +31,7 @@ struct rusage_t }; #define RUSAGE_T struct rusage_t -#ifdef HAVE_RUSAGE -#define GETRUSAGE(X) \ - getrusage(RUSAGE_SELF, &((X)->cpu)); \ - gettimeofday(&recent_time, NULL); (X)->real = recent_time -#else -#define GETRUSAGE(X) \ - gettimeofday(&recent_time, NULL); (X)->real = recent_time -#endif /* HAVE_RUSAGE */ +#define GETRUSAGE(X) thread_getrusage(X) /* Linked list of thread. */ struct thread_list @@ -99,6 +92,13 @@ struct cpu_thread_history unsigned char types; }; +/* Clocks supported by Quagga */ +enum quagga_clkid { + QUAGGA_CLK_REALTIME = 0, /* ala gettimeofday() */ + QUAGGA_CLK_MONOTONIC, /* monotonic, against an indeterminate base */ + QUAGGA_CLK_REALTIME_STABILISED, /* like realtime, but non-decrementing */ +}; + /* Thread types. */ #define THREAD_READ 0 #define THREAD_WRITE 1 @@ -192,8 +192,17 @@ extern void thread_call (struct thread *); extern unsigned long thread_timer_remain_second (struct thread *); extern int thread_should_yield (struct thread *); +/* Internal libzebra exports */ +extern void thread_getrusage (RUSAGE_T *); extern struct cmd_element show_thread_cpu_cmd; +/* replacements for the system gettimeofday(), clock_gettime() and + * time() functions, providing support for non-decrementing clock on + * all systems, and fully monotonic on /some/ systems. + */ +extern int quagga_gettime (enum quagga_clkid, struct timeval *); +extern time_t quagga_time (time_t *); + /* Returns elapsed real (wall clock) time. */ extern unsigned long thread_consumed_time(RUSAGE_T *after, RUSAGE_T *before, unsigned long *cpu_time_elapsed); @@ -202,5 +211,6 @@ extern unsigned long thread_consumed_time(RUSAGE_T *after, RUSAGE_T *before, be used instead of calling gettimeofday if a recent value is sufficient. This is guaranteed to be refreshed before a thread is called. */ extern struct timeval recent_time; - +/* Similar to recent_time, but a monotonically increasing time value */ +extern struct timeval recent_relative_time (void); #endif /* _ZEBRA_THREAD_H */ -- cgit v1.2.3