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top: provide more accurate cpu usage stats for startup

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The top program already incorporated a modest delay at
startup so that some minimal process cpu history could
be established. However, Summary Area system level cpu
statistic history reflected usage since boot. As such,
unchanging % values would be shown with every restart.

This commit just adopts the same approach used in task
%CPU history for the Summary Area statistics. In other
words, it introduces a 'priming read' at startup as is
found in the newlib implementation for the <stat> API.

Reference(s):
https://gitlab.com/procps-ng/procps/merge_requests/42

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2017-03-23 00:00:00 -05:00 committed by Craig Small
parent 909b37d755
commit 56d79b9d13
2 changed files with 21 additions and 23 deletions
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42
top/top.c
View File

@ -92,6 +92,7 @@ static int Rc_questions;
static unsigned Pg2K_shft = 0;
/* SMP, Irix/Solaris mode, Linux 2.5.xx support */
static CPU_t *Cpu_tics;
static int Cpu_faux_tot;
static float Cpu_pmax;
static const char *Cpu_States_fmts;
@ -2347,10 +2348,10 @@ static void zap_fieldstab (void) {
* This guy's modeled on libproc's 'eight_cpu_numbers' function except
* we preserve all cpu data in our CPU_t array which is organized
* as follows:
* cpus[0] thru cpus[n] == tics for each separate cpu
* cpus[sumSLOT] == tics from the 1st /proc/stat line
* [ and beyond sumSLOT == tics for each cpu NUMA node ] */
static CPU_t *cpus_refresh (CPU_t *cpus) {
* Cpu_tics[0] thru Cpu_tics[n] == tics for each separate cpu
* Cpu_tics[sumSLOT] == tics from /proc/stat line #1
* [ and beyond sumSLOT == tics for each cpu NUMA node ] */
static void cpus_refresh (void) {
#define sumSLOT ( smp_num_cpus )
#define totSLOT ( 1 + smp_num_cpus + Numa_node_tot)
static FILE *fp = NULL;
@ -2368,7 +2369,7 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
sav_slot = sumSLOT;
zap_fieldstab();
if (fp) { fclose(fp); fp = NULL; }
if (cpus) { free(cpus); cpus = NULL; }
if (Cpu_tics) free(Cpu_tics);
}
/* by opening this file once, we'll avoid the hit on minor page faults
@ -2378,7 +2379,7 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
error_exit(fmtmk(N_fmt(FAIL_statopn_fmt), strerror(errno)));
/* note: we allocate one more CPU_t via totSLOT than 'cpus' so that a
slot can hold tics representing the /proc/stat cpu summary */
cpus = alloc_c(totSLOT * sizeof(CPU_t));
Cpu_tics = alloc_c(totSLOT * sizeof(CPU_t));
}
rewind(fp);
fflush(fp);
@ -2401,7 +2402,7 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
#undef buffGRW
// remember from last time around
sum_ptr = &cpus[sumSLOT];
sum_ptr = &Cpu_tics[sumSLOT];
memcpy(&sum_ptr->sav, &sum_ptr->cur, sizeof(CT_t));
// then value the last slot with the cpu summary line
if (4 > sscanf(bp, "cpu %llu %llu %llu %llu %llu %llu %llu %llu"
@ -2428,7 +2429,7 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
// now value each separate cpu's tics...
for (i = 0; i < sumSLOT; i++) {
CPU_t *cpu_ptr = &cpus[i]; // avoid gcc subscript bloat
CPU_t *cpu_ptr = &Cpu_tics[i]; // avoid gcc subscript bloat
#ifdef PRETEND8CPUS
bp = buf;
#endif
@ -2439,7 +2440,6 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
, &cpu_ptr->cur.u, &cpu_ptr->cur.n, &cpu_ptr->cur.s
, &cpu_ptr->cur.i, &cpu_ptr->cur.w, &cpu_ptr->cur.x
, &cpu_ptr->cur.y, &cpu_ptr->cur.z)) {
memmove(cpu_ptr, sum_ptr, sizeof(CPU_t));
break; // tolerate cpus taken offline
}
@ -2479,8 +2479,6 @@ static CPU_t *cpus_refresh (CPU_t *cpus) {
} // end: for each cpu
Cpu_faux_tot = i; // tolerate cpus taken offline
return cpus;
#undef sumSLOT
#undef totSLOT
} // end: cpus_refresh
@ -5156,7 +5154,6 @@ static void summary_hlp (CPU_t *cpu, const char *pfx) {
static void summary_show (void) {
#define isROOM(f,n) (CHKw(w, f) && Msg_row + (n) < Screen_rows - 1)
#define anyFLG 0xffffff
static CPU_t *smpcpu = NULL;
WIN_t *w = Curwin; // avoid gcc bloat with a local copy
char tmp[MEDBUFSIZ];
int i;
@ -5179,7 +5176,7 @@ static void summary_show (void) {
, Frame_stopped, Frame_zombied));
Msg_row += 1;
smpcpu = cpus_refresh(smpcpu);
cpus_refresh();
#ifndef NUMA_DISABLE
if (!Numa_node_tot) goto numa_nope;
@ -5187,11 +5184,11 @@ static void summary_show (void) {
if (CHKw(w, View_CPUNOD)) {
if (Numa_node_sel < 0) {
// display the 1st /proc/stat line, then the nodes (if room)
summary_hlp(&smpcpu[smp_num_cpus], N_txt(WORD_allcpus_txt));
summary_hlp(&Cpu_tics[smp_num_cpus], N_txt(WORD_allcpus_txt));
Msg_row += 1;
// display each cpu node's states
for (i = 0; i < Numa_node_tot; i++) {
CPU_t *nod_ptr = &smpcpu[1 + smp_num_cpus + i];
CPU_t *nod_ptr = &Cpu_tics[1 + smp_num_cpus + i];
if (!isROOM(anyFLG, 1)) break;
#ifndef OFF_NUMASKIP
if (nod_ptr->id) {
@ -5206,13 +5203,13 @@ static void summary_show (void) {
} else {
// display the node summary, then the associated cpus (if room)
snprintf(tmp, sizeof(tmp), N_fmt(NUMA_nodenam_fmt), Numa_node_sel);
summary_hlp(&smpcpu[1 + smp_num_cpus + Numa_node_sel], tmp);
summary_hlp(&Cpu_tics[1 + smp_num_cpus + Numa_node_sel], tmp);
Msg_row += 1;
for (i = 0; i < Cpu_faux_tot; i++) {
if (Numa_node_sel == smpcpu[i].node) {
if (Numa_node_sel == Cpu_tics[i].node) {
if (!isROOM(anyFLG, 1)) break;
snprintf(tmp, sizeof(tmp), N_fmt(WORD_eachcpu_fmt), smpcpu[i].id);
summary_hlp(&smpcpu[i], tmp);
snprintf(tmp, sizeof(tmp), N_fmt(WORD_eachcpu_fmt), Cpu_tics[i].id);
summary_hlp(&Cpu_tics[i], tmp);
Msg_row += 1;
}
}
@ -5222,14 +5219,14 @@ numa_nope:
#endif
if (CHKw(w, View_CPUSUM)) {
// display just the 1st /proc/stat line
summary_hlp(&smpcpu[Cpu_faux_tot], N_txt(WORD_allcpus_txt));
summary_hlp(&Cpu_tics[Cpu_faux_tot], N_txt(WORD_allcpus_txt));
Msg_row += 1;
} else {
// display each cpu's states separately, screen height permitting...
for (i = 0; i < Cpu_faux_tot; i++) {
snprintf(tmp, sizeof(tmp), N_fmt(WORD_eachcpu_fmt), smpcpu[i].id);
summary_hlp(&smpcpu[i], tmp);
snprintf(tmp, sizeof(tmp), N_fmt(WORD_eachcpu_fmt), Cpu_tics[i].id);
summary_hlp(&Cpu_tics[i], tmp);
Msg_row += 1;
if (!isROOM(anyFLG, 1)) break;
}
@ -5697,6 +5694,7 @@ static void frame_make (void) {
// whoa either first time or thread/task mode change, (re)prime the pump...
if (Pseudo_row == PROC_XTRA) {
cpus_refresh();
procs_refresh();
usleep(LIB_USLEEP);
putp(Cap_clr_scr);

2
top/top.h
View File

@ -730,7 +730,7 @@ typedef struct WIN_t {
//atic inline void widths_resize (void);
//atic void zap_fieldstab (void);
/*------ Library Interface ---------------------------------------------*/
//atic CPU_t *cpus_refresh (CPU_t *cpus);
//atic void cpus_refresh (void);
#ifdef OFF_HST_HASH
//atic inline HST_t *hstbsrch (HST_t *hst, int max, int pid);
#else