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top: avoid yet more overhead of accessing /proc/status

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After discovering those terrible costs associated with
/proc/status vs. /proc/stat, the build_header function
changed to favor the latter for a field found in both.

Well, low-and-behold, this top program still used some
flags that needlessly caused 'status' to still be read
when 'statm' could have served. And, while top's needs
require conversion from pages to KiB, that's still far
less costly than reading that gosh darn 'status' file.

[ this patch parallels similar changes to newlib top ]

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner 2016-08-20 00:00:00 -05:00 committed by Craig Small
parent 7df87ea7cf
commit 5313852596
1 changed files with 8 additions and 8 deletions
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16
top/top.c
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@ -282,7 +282,7 @@ SCB_NUMx(PGD, pgrp)
SCB_NUMx(PID, tid)
SCB_NUMx(PPD, ppid)
SCB_NUMx(PRI, priority)
SCB_NUM1(RES, vm_rss) // also serves MEM !
SCB_NUM1(RES, resident) // also serves MEM !
SCB_NUM1(RZA, vm_rss_anon)
SCB_NUM1(RZF, vm_rss_file)
SCB_NUM1(RZL, vm_lock)
@ -1743,21 +1743,21 @@ static FLD_t Fieldstab[] = {
{ 6, -1, A_right, SF(TME), L_stat },
{ 9, -1, A_right, SF(TME), L_stat }, // EU_TM2 slot
#ifdef BOOST_PERCNT
{ 5, -1, A_right, SF(RES), L_status }, // EU_MEM slot
{ 5, -1, A_right, SF(RES), L_statm }, // EU_MEM slot
#else
{ 4, -1, A_right, SF(RES), L_status }, // EU_MEM slot
{ 4, -1, A_right, SF(RES), L_statm }, // EU_MEM slot
#endif
#ifndef NOBOOST_MEMS
{ 7, SK_Kb, A_right, SF(VRT), L_statm },
{ 6, SK_Kb, A_right, SF(SWP), L_status },
{ 6, SK_Kb, A_right, SF(RES), L_status },
{ 6, SK_Kb, A_right, SF(RES), L_statm },
{ 6, SK_Kb, A_right, SF(COD), L_statm },
{ 7, SK_Kb, A_right, SF(DAT), L_statm },
{ 6, SK_Kb, A_right, SF(SHR), L_statm },
#else
{ 5, SK_Kb, A_right, SF(VRT), L_statm },
{ 4, SK_Kb, A_right, SF(SWP), L_status },
{ 4, SK_Kb, A_right, SF(RES), L_status },
{ 4, SK_Kb, A_right, SF(RES), L_statm },
{ 4, SK_Kb, A_right, SF(COD), L_statm },
{ 5, SK_Kb, A_right, SF(DAT), L_statm },
{ 4, SK_Kb, A_right, SF(SHR), L_statm },
@ -1940,7 +1940,7 @@ static void build_headers (void) {
if (hdrmax + w->hdrcaplen < (x = strlen(w->columnhdr))) hdrmax = x - w->hdrcaplen;
#endif
// with forest view mode, we'll need tgid, ppid & start_time...
if (CHKw(w, Show_FOREST)) Frames_libflags |= (L_status | L_stat);
if (CHKw(w, Show_FOREST)) Frames_libflags |= L_stat;
// for 'busy' only processes, we'll need pcpu (utime & stime)...
if (!CHKw(w, Show_IDLEPS)) Frames_libflags |= L_stat;
// we must also accommodate an out of view sort field...
@ -5405,7 +5405,7 @@ static const char *task_show (const WIN_t *q, const proc_t *p) {
cp = make_str(p->lxcname, W, Js, EU_LXC);
break;
case EU_MEM:
cp = scale_pcnt((float)p->vm_rss * 100 / kb_main_total, W, Jn);
cp = scale_pcnt((float)pages2K(p->resident) * 100 / kb_main_total, W, Jn);
break;
case EU_NCE:
cp = make_num(p->nice, W, Jn, AUTOX_NO, 1);
@ -5442,7 +5442,7 @@ static const char *task_show (const WIN_t *q, const proc_t *p) {
cp = make_num(p->priority, W, Jn, AUTOX_NO, 0);
break;
case EU_RES:
cp = scale_mem(S, p->vm_rss, W, Jn);
cp = scale_mem(S, pages2K(p->resident), W, Jn);
break;
case EU_RZA:
cp = scale_mem(S, p->vm_rss_anon, W, Jn);