From 1fd8e66203906f6e245959de1bc293556e6ab7fa Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 10 Aug 2017 14:10:56 +0200 Subject: [PATCH] ps: stop using AT_CLKTCK, there are more standard ways function old new delta ps_main 537 558 +21 func_time 66 59 -7 get_kernel_HZ 102 - -102 ------------------------------------------------------------------------------ (add/remove: 0/1 grow/shrink: 1/1 up/down: 21/-109) Total: -88 bytes Signed-off-by: Denys Vlasenko --- procps/ps.c | 105 +++++----------------------------------------------- 1 file changed, 10 insertions(+), 95 deletions(-) diff --git a/procps/ps.c b/procps/ps.c index e004d25bb..fab8c81eb 100644 --- a/procps/ps.c +++ b/procps/ps.c @@ -145,12 +145,6 @@ static unsigned long get_uptime(void) #endif #if ENABLE_DESKTOP - -#include /* for times() */ -#ifndef AT_CLKTCK -# define AT_CLKTCK 17 -#endif - /* TODO: * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html * specifies (for XSI-conformant systems) following default columns @@ -187,7 +181,9 @@ struct globals { char *buffer; unsigned terminal_width; #if ENABLE_FEATURE_PS_TIME +# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__) unsigned kernel_HZ; +# endif unsigned long seconds_since_boot; #endif } FIX_ALIASING; @@ -198,92 +194,15 @@ struct globals { #define need_flags (G.need_flags ) #define buffer (G.buffer ) #define terminal_width (G.terminal_width ) -#define kernel_HZ (G.kernel_HZ ) #define INIT_G() do { setup_common_bufsiz(); } while (0) #if ENABLE_FEATURE_PS_TIME -/* for ELF executables, notes are pushed before environment and args */ -/* try "LD_SHOW_AUXV=1 /bin/true" */ -static uintptr_t find_elf_note(uintptr_t findme) -{ - uintptr_t *ep = (uintptr_t *) environ; - - while (*ep++) - continue; - while (*ep) { - if (ep[0] == findme) { - return ep[1]; - } - ep += 2; - } - return -1; -} - -# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS -static unsigned get_HZ_by_waiting(void) -{ - struct timeval tv1, tv2; - unsigned t1, t2, r, hz; - unsigned cnt = cnt; /* for compiler */ - int diff; - - r = 0; - - /* Wait for times() to reach new tick */ - t1 = times(NULL); - do { - t2 = times(NULL); - } while (t2 == t1); - gettimeofday(&tv2, NULL); - - do { - t1 = t2; - tv1.tv_usec = tv2.tv_usec; - - /* Wait exactly one times() tick */ - do { - t2 = times(NULL); - } while (t2 == t1); - gettimeofday(&tv2, NULL); - - /* Calculate ticks per sec, rounding up to even */ - diff = tv2.tv_usec - tv1.tv_usec; - if (diff <= 0) diff += 1000000; - hz = 1000000u / (unsigned)diff; - hz = (hz+1) & ~1; - - /* Count how many same hz values we saw */ - if (r != hz) { - r = hz; - cnt = 0; - } - cnt++; - } while (cnt < 3); /* exit if saw 3 same values */ - - return r; -} +# if ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__) +# define get_kernel_HZ() (G.kernel_HZ) # else -static inline unsigned get_HZ_by_waiting(void) -{ - /* Better method? */ - return 100; -} + /* non-ancient Linux standardized on 100 for "times" freq */ +# define get_kernel_HZ() ((unsigned)100) # endif - -static unsigned get_kernel_HZ(void) -{ - if (kernel_HZ) - return kernel_HZ; - - /* Works for ELF only, Linux 2.4.0+ */ - kernel_HZ = find_elf_note(AT_CLKTCK); - if (kernel_HZ == (unsigned)-1) - kernel_HZ = get_HZ_by_waiting(); - - G.seconds_since_boot = get_uptime(); - - return kernel_HZ; -} #endif /* Print value to buf, max size+1 chars (including trailing '\0') */ @@ -375,26 +294,21 @@ static void func_tty(char *buf, int size, const procps_status_t *ps) } #if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS - static void func_rgroup(char *buf, int size, const procps_status_t *ps) { safe_strncpy(buf, get_cached_groupname(ps->rgid), size+1); } - static void func_ruser(char *buf, int size, const procps_status_t *ps) { safe_strncpy(buf, get_cached_username(ps->ruid), size+1); } - static void func_nice(char *buf, int size, const procps_status_t *ps) { sprintf(buf, "%*d", size, ps->niceness); } - #endif #if ENABLE_FEATURE_PS_TIME - static void func_etime(char *buf, int size, const procps_status_t *ps) { /* elapsed time [[dd-]hh:]mm:ss; here only mm:ss */ @@ -402,13 +316,11 @@ static void func_etime(char *buf, int size, const procps_status_t *ps) unsigned ss; mm = ps->start_time / get_kernel_HZ(); - /* must be after get_kernel_HZ()! */ mm = G.seconds_since_boot - mm; ss = mm % 60; mm /= 60; snprintf(buf, size+1, "%3lu:%02u", mm, ss); } - static void func_time(char *buf, int size, const procps_status_t *ps) { /* cumulative time [[dd-]hh:]mm:ss; here only mm:ss */ @@ -420,7 +332,6 @@ static void func_time(char *buf, int size, const procps_status_t *ps) mm /= 60; snprintf(buf, size+1, "%3lu:%02u", mm, ss); } - #endif #if ENABLE_SELINUX @@ -627,6 +538,10 @@ int ps_main(int argc UNUSED_PARAM, char **argv) }; INIT_G(); + G.seconds_since_boot = get_uptime(); +#if ENABLE_FEATURE_PS_TIME && (ENABLE_FEATURE_PS_UNUSUAL_SYSTEMS || !defined(__linux__)) + G.kernel_HZ = bb_clk_tck(); /* this is sysconf(_SC_CLK_TCK) */ +#endif // POSIX: // -a Write information for all processes associated with terminals -- 2.25.1