--- ps/common.h
+++ ps/common.h	2008-09-16 16:57:14.862641102 +0000
@@ -302,6 +302,7 @@ extern int             running_only;
 extern int             screen_cols;
 extern int             screen_rows;
 extern unsigned long   seconds_since_boot;
+extern unsigned long long jiffies_since_boot;
 extern selection_node *selection_list;
 extern unsigned        simple_select;
 extern sort_node      *sort_list;
--- ps/global.c
+++ ps/global.c	2008-09-16 16:56:28.218297961 +0000
@@ -70,6 +70,7 @@ int             prefer_bsd_defaults = -1
 int             screen_cols = -1;
 int             screen_rows = -1;
 unsigned long   seconds_since_boot = -1;
+unsigned long long  jiffies_since_boot = -1;
 selection_node *selection_list = (selection_node *)0xdeadbeef;
 unsigned        simple_select = 0xffffffff;
 sort_node      *sort_list = (sort_node *)0xdeadbeef; /* ready-to-use sort list */
@@ -357,6 +358,7 @@ static const char *set_personality(void)
 /************ Call this to reinitialize everything ***************/
 void reset_global(void){
   static proc_t p;
+  double uptime_secs;
   reset_selection_list();
   look_up_our_self(&p);
   set_screen_size();
@@ -380,7 +382,8 @@ void reset_global(void){
   negate_selection      = 0;
   page_size             = getpagesize();
   running_only          = 0;
-  seconds_since_boot    = uptime(0,0);
+  seconds_since_boot    = uptime(&uptime_secs,0);
+  jiffies_since_boot	= ((long double)uptime_secs * Hertz);
   selection_list        = NULL;
   simple_select         = 0;
   sort_list             = NULL;
--- ps/output.c
+++ ps/output.c	2010-02-18 11:21:40.112125962 +0000
@@ -426,11 +426,12 @@ static int pr_etime(char *restrict const
 static int pr_c(char *restrict const outbuf, const proc_t *restrict const pp){
   unsigned long long total_time;   /* jiffies used by this process */
   unsigned pcpu = 0;               /* scaled %cpu, 99 means 99% */
-  unsigned long long seconds;      /* seconds of process life */
+  unsigned long long jiffies;      /* jiffies of process life */
+  double uptime_secs;
   total_time = pp->utime + pp->stime;
   if(include_dead_children) total_time += (pp->cutime + pp->cstime);
-  seconds = seconds_since_boot - pp->start_time / Hertz;
-  if(seconds) pcpu = (total_time * 100ULL / Hertz) / seconds;
+  jiffies = jiffies_since_boot - pp->start_time;
+  if(jiffies) pcpu = (total_time * 100ULL) / jiffies;
   if (pcpu > 99U) pcpu = 99U;
   return snprintf(outbuf, COLWID, "%2u", pcpu);
 }
@@ -438,24 +439,26 @@ static int pr_c(char *restrict const out
 static int pr_pcpu(char *restrict const outbuf, const proc_t *restrict const pp){
   unsigned long long total_time;   /* jiffies used by this process */
   unsigned pcpu = 0;               /* scaled %cpu, 999 means 99.9% */
-  unsigned long long seconds;      /* seconds of process life */
+  unsigned long long jiffies;      /* jiffies of process life */
+  double uptime_secs;
   total_time = pp->utime + pp->stime;
   if(include_dead_children) total_time += (pp->cutime + pp->cstime);
-  seconds = seconds_since_boot - pp->start_time / Hertz;
-  if(seconds) pcpu = (total_time * 1000ULL / Hertz) / seconds;
-  if (pcpu > 999U)
-    return snprintf(outbuf, COLWID, "%u", pcpu/10U);
+  jiffies = jiffies_since_boot - pp->start_time;
+  if(jiffies) pcpu = (total_time * 1000ULL) / jiffies;
+  if (pcpu/10U => 100U)		    /* do not confuse the user by scale effects */
+    return snprintf(outbuf, COLWID, "100");
   return snprintf(outbuf, COLWID, "%u.%u", pcpu/10U, pcpu%10U);
 }
 /* this is a "per-mill" format, like %cpu with no decimal point */
 static int pr_cp(char *restrict const outbuf, const proc_t *restrict const pp){
   unsigned long long total_time;   /* jiffies used by this process */
   unsigned pcpu = 0;               /* scaled %cpu, 999 means 99.9% */
-  unsigned long long seconds;      /* seconds of process life */
+  unsigned long long jiffies;      /* jiffies of process life */
+  double uptime_secs;
   total_time = pp->utime + pp->stime;
   if(include_dead_children) total_time += (pp->cutime + pp->cstime);
-  seconds = seconds_since_boot - pp->start_time / Hertz ;
-  if(seconds) pcpu = (total_time * 1000ULL / Hertz) / seconds;
+  jiffies = jiffies_since_boot - pp->start_time;
+  if(jiffies) pcpu = (total_time * 1000ULL) / jiffies;
   if (pcpu > 999U) pcpu = 999U;
   return snprintf(outbuf, COLWID, "%3u", pcpu);
 }