[Buildroot] Add 'IRIX mode' to top.
David Laight
David.Laight at ACULAB.COM
Thu Nov 11 12:28:21 UTC 2021
Add 'IRIX mode' to top.
On a multi-cpu system 'IRIX mode' displays a singled threaded process
that is spinning as using 100% cpu.
This is generally more useful than the current 'Solaris mode' that
reports 100/num_cpu% cpu.
A multi-threaded program that is busy on multiple cpu will
show a cpu use > 100%.
Enabled by -I on the command line or 'i' on stdin.
Remove some (uint16_t) casts from the 'delta jiffies' value.
With enough cpu, fast enough HZ, and long enough delay I think
64k can be exceeded.
I doubt intended efficiency of 16x16 multiple makes any difference.
Signed-off-by: David Laight <david.laight at aculab.com>
---
It might be worth adding an extra column for processes with a
lot of busy threads on systems with a lot of cpu.
Note that this is a normal diff from an installed tree.
I don't have the git tree.
--- top.c.1.33 2021-11-11 09:49:08.165982660 +0000
+++ top.c 2021-11-11 11:28:50.155674293 +0000
@@ -166,6 +166,7 @@
#endif
#if ENABLE_FEATURE_TOP_SMP_CPU
smallint smp_cpu_info; /* one/many cpu info lines? */
+ smallint irix_mode; /* 100% => one cpu busy */
#endif
unsigned lines; /* screen height */
#if ENABLE_FEATURE_TOP_INTERACTIVE
@@ -202,6 +203,7 @@
#define sort_field (G.sort_field )
#define inverted (G.inverted )
#define smp_cpu_info (G.smp_cpu_info )
+#define irix_mode (G.irix_mode )
#define initial_settings (G.initial_settings )
#define sort_function (G.sort_function )
#define prev_hist (G.prev_hist )
@@ -223,8 +225,9 @@
OPT_n = (1 << 1),
OPT_b = (1 << 2),
OPT_H = (1 << 3),
- OPT_m = (1 << 4),
- OPT_EOF = (1 << 5), /* pseudo: "we saw EOF in stdin" */
+ OPT_I = (1 << 4),
+ OPT_m = (1 << 5),
+ OPT_EOF = (1 << 6), /* pseudo: "we saw EOF in stdin" */
};
#define OPT_BATCH_MODE (option_mask32 & OPT_b)
@@ -314,6 +317,13 @@
return;
#else
if (!smp_cpu_info) {
+ if (irix_mode && !num_cpus) {
+ jiffy_counts_t dummy_jif;
+ while (read_cpu_jiffy(fp, &dummy_jif) >= 4)
+ num_cpus++;
+ if (!num_cpus)
+ irix_mode = 0;
+ }
fclose(fp);
return;
}
@@ -328,8 +338,10 @@
break;
num_cpus++;
}
- if (num_cpus == 0) /* /proc/stat with only "cpu ..." line?! */
+ if (num_cpus == 0) { /* /proc/stat with only "cpu ..." line?! */
smp_cpu_info = 0;
+ irix_mode = 0;
+ }
cpu_prev_jif = xzalloc(sizeof(cpu_prev_jif[0]) * num_cpus);
@@ -602,6 +614,28 @@
return meminfo[MI_MEMTOTAL];
}
+#if ENABLE_FEATURE_TOP_DECIMALS
+# define UPSCALE 1000
+# define FMT "%s"
+# define SHOW_STAT(name, buf_id) fmt_proc_pc(name, buf_id)
+static NOINLINE const char *fmt_proc_pc(unsigned value, unsigned buf_id)
+{
+ static char bufs[2][16];
+ char *buf = bufs[buf_id];
+
+ if (value >= 1000)
+ snprintf(buf, 16, "%5u", value/10);
+ else
+ snprintf(buf, 16, "%3u.%c", value/10, '0' + (value % 10));
+ return buf;
+}
+
+#else
+# define UPSCALE 100
+# define FMT "%4u%%"
+# define SHOW_STAT(name, buf_id) name
+#endif
+
static NOINLINE void display_process_list(int lines_rem, int scr_width)
{
enum {
@@ -627,17 +661,6 @@
" COMMAND");
lines_rem--;
-#if ENABLE_FEATURE_TOP_DECIMALS
-# define UPSCALE 1000
-# define CALC_STAT(name, val) div_t name = div((val), 10)
-# define SHOW_STAT(name) name.quot, '0'+name.rem
-# define FMT "%3u.%c"
-#else
-# define UPSCALE 100
-# define CALC_STAT(name, val) unsigned name = (val)
-# define SHOW_STAT(name) name
-# define FMT "%4u%%"
-#endif
/*
* %VSZ = s->vsz/MemTotal
*/
@@ -664,14 +687,18 @@
* we assume that unsigned is at least 32-bit.
*/
pcpu_shift = 6;
- pcpu_scale = UPSCALE*64 * (uint16_t)busy_jifs;
+ pcpu_scale = UPSCALE*64 * busy_jifs;
if (pcpu_scale == 0)
pcpu_scale = 1;
while (pcpu_scale < (1U << (BITS_PER_INT-2))) {
pcpu_scale *= 4;
pcpu_shift += 2;
}
- tmp_unsigned = (uint16_t)(cur_jif.total - prev_jif.total) * total_pcpu;
+ tmp_unsigned = (cur_jif.total - prev_jif.total) * total_pcpu;
+#if ENABLE_FEATURE_TOP_SMP_CPU
+ if (irix_mode && num_cpus)
+ tmp_unsigned /= num_cpus;
+#endif
if (tmp_unsigned != 0)
pcpu_scale /= tmp_unsigned;
/* we want (s->pcpu * pcpu_scale) to never overflow */
@@ -692,9 +719,9 @@
char vsz_str_buf[8];
unsigned col;
- CALC_STAT(pmem, (s->vsz*pmem_scale + pmem_half) >> pmem_shift);
+ unsigned pmem = (s->vsz*pmem_scale + pmem_half) >> pmem_shift;
#if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
- CALC_STAT(pcpu, (s->pcpu*pcpu_scale + pcpu_half) >> pcpu_shift);
+ unsigned pcpu = (s->pcpu*pcpu_scale + pcpu_half) >> pcpu_shift;
#endif
smart_ulltoa5(s->vsz, vsz_str_buf, " mgtpezy");
@@ -706,9 +733,9 @@
" ",
s->pid, s->ppid, get_cached_username(s->uid),
s->state, vsz_str_buf,
- SHOW_STAT(pmem)
+ SHOW_STAT(pmem, 0)
IF_FEATURE_TOP_SMP_PROCESS(, s->last_seen_on_cpu)
- IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(, SHOW_STAT(pcpu))
+ IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(, SHOW_STAT(pcpu, 1))
);
if ((int)(scr_width - col) > 1)
read_cmdline(line_buf + col, scr_width - col, s->pid, s->comm);
@@ -1034,6 +1061,10 @@
get_jiffy_counts();
continue;
}
+ if (c == 'i') {
+ irix_mode ^= 1;
+ continue;
+ }
# endif
# endif
break; /* unknown key -> force refresh */
@@ -1120,7 +1151,7 @@
/* all args are options; -n NUM */
make_all_argv_opts(argv); /* options can be specified w/o dash */
- col = getopt32(argv, "d:n:bHm", &str_interval, &str_iterations);
+ col = getopt32(argv, "d:n:bHIm", &str_interval, &str_iterations);
/* NB: -m and -H are accepted even if not configured */
#if ENABLE_FEATURE_TOPMEM
if (col & OPT_m) /* -m (busybox specific) */
@@ -1145,6 +1176,10 @@
scan_mask |= PSSCAN_TASKS;
}
#endif
+#if ENABLE_FEATURE_TOP_SMP_CPU
+ if (col & OPT_I)
+ irix_mode = 1;
+#endif
/* change to /proc */
xchdir("/proc");
-
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