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nmeter: stop using data/bss; reduce amount of reads from /proc

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# size */*/nmeter.o
   text    data     bss     dec     hex filename
   4366      80      16    4462    116e busybox.t0/miscutils/nmeter.o
   4386       0       0    4386    1122 busybox.t2/miscutils/nmeter.o
This commit is contained in:
Denis Vlasenko 2007-05-30 14:48:38 +00:00
parent 0b3b41b62a
commit 199c0d542b
1 changed files with 89 additions and 48 deletions
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137
miscutils/nmeter.c
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@ -17,33 +17,67 @@
typedef unsigned long long ullong; typedef unsigned long long ullong;
enum { proc_file_size = 4096 }; enum { PROC_FILE_SIZE = 4096 };
typedef struct proc_file { typedef struct proc_file {
const char *name;
int gen;
char *file; char *file;
//const char *name;
smallint last_gen;
} proc_file; } proc_file;
static proc_file proc_stat = { "/proc/stat", -1 }; static const char *const proc_name[] = {
static proc_file proc_loadavg = { "/proc/loadavg", -1 }; "stat", // Must match the order of proc_file's!
static proc_file proc_net_dev = { "/proc/net/dev", -1 }; "loadavg",
static proc_file proc_meminfo = { "/proc/meminfo", -1 }; "net/dev",
static proc_file proc_diskstats = { "/proc/diskstats", -1 }; "meminfo",
// Sample # "diskstats",
static int gen = -1; "sys/fs/file-nr",
// Linux 2.6? (otherwise assumes 2.4) };
static int is26 = 0;
static struct timeval tv; struct globals {
static int delta = 1000000; // Sample generation flip-flop
static int deltanz = 1000000; smallint gen;
static int need_seconds = 0; // Linux 2.6? (otherwise assumes 2.4)
static const char *final_str = "\n"; smallint is26;
// 1 if sample delay is not an integer fraction of a second
smallint need_seconds;
char *cur_outbuf;
const char *final_str;
int delta;
int deltanz;
struct timeval tv;
#define first_proc_file proc_stat
proc_file proc_stat; // Must match the order of proc_name's!
proc_file proc_loadavg;
proc_file proc_net_dev;
proc_file proc_meminfo;
proc_file proc_diskstats;
proc_file proc_sys_fs_filenr;
};
#define G (*ptr_to_globals)
#define gen (G.gen )
#define is26 (G.is26 )
#define need_seconds (G.need_seconds )
#define cur_outbuf (G.cur_outbuf )
#define final_str (G.final_str )
#define delta (G.delta )
#define deltanz (G.deltanz )
#define tv (G.tv )
#define proc_stat (G.proc_stat )
#define proc_loadavg (G.proc_loadavg )
#define proc_net_dev (G.proc_net_dev )
#define proc_meminfo (G.proc_meminfo )
#define proc_diskstats (G.proc_diskstats )
#define proc_sys_fs_filenr (G.proc_sys_fs_filenr)
// We depend on this being a char[], not char* - we take sizeof() of it // We depend on this being a char[], not char* - we take sizeof() of it
#define outbuf bb_common_bufsiz1 #define outbuf bb_common_bufsiz1
static char *cur_outbuf = outbuf;
#define INIT_G() do { \
cur_outbuf = outbuf; \
final_str = "\n"; \
deltanz = delta = 1000000; \
} while (0)
static inline void reset_outbuf(void) static inline void reset_outbuf(void)
{ {
@ -85,27 +119,31 @@ static void put_question_marks(int count)
put_c('?'); put_c('?');
} }
static int readfile_z(char *buf, int sz, const char* fname) static void readfile_z(char *buf, int sz, const char* fname)
{ {
sz = open_read_close(fname, buf, sz-1); // open_read_close() will do two reads in order to be sure we are at EOF,
if (sz < 0) { // and we don't need/want that.
buf[0] = '\0'; // sz = open_read_close(fname, buf, sz-1);
return 1;
int fd = xopen(fname, O_RDONLY);
buf[0] = '\0';
if (fd >= 0) {
sz = read(fd, buf, sz-1);
if (sz > 0) buf[sz] = '\0';
close(fd);
} }
buf[sz] = '\0';
return 0;
} }
static const char* get_file(proc_file *pf) static const char* get_file(proc_file *pf)
{ {
if (pf->gen != gen) { if (pf->last_gen != gen) {
pf->gen = gen; pf->last_gen = gen;
// We allocate proc_file_size bytes. This wastes memory, // We allocate PROC_FILE_SIZE bytes. This wastes memory,
// but allows us to allocate only once (at first sample) // but allows us to allocate only once (at first sample)
// per proc file, and reuse buffer for each sample // per proc file, and reuse buffer for each sample
if (!pf->file) if (!pf->file)
pf->file = xmalloc(proc_file_size); pf->file = xmalloc(PROC_FILE_SIZE);
readfile_z(pf->file, proc_file_size, pf->name); readfile_z(pf->file, PROC_FILE_SIZE, proc_name[pf - &first_proc_file]);
} }
return pf->file; return pf->file;
} }
@ -242,10 +280,10 @@ static s_stat* init_literal(void)
static s_stat* init_delay(const char *param) static s_stat* init_delay(const char *param)
{ {
delta = strtol(param, NULL, 0)*1000; delta = bb_strtoi(param, NULL, 0) * 1000;
deltanz = delta > 0 ? delta : 1; deltanz = delta > 0 ? delta : 1;
need_seconds = (1000000%deltanz) != 0; need_seconds = (1000000%deltanz) != 0;
return (s_stat*)0; return NULL;
} }
static s_stat* init_cr(const char *param) static s_stat* init_cr(const char *param)
@ -281,7 +319,7 @@ static void collect_cpu(cpu_stat *s)
return; return;
} }
for (i=0; i<CPU_FIELDCNT; i++) { for (i = 0; i < CPU_FIELDCNT; i++) {
ullong old = s->old[i]; ullong old = s->old[i];
if (data[i] < old) old = data[i]; //sanitize if (data[i] < old) old = data[i]; //sanitize
s->old[i] = data[i]; s->old[i] = data[i];
@ -289,7 +327,7 @@ static void collect_cpu(cpu_stat *s)
} }
if (all) { if (all) {
for (i=0; i<CPU_FIELDCNT; i++) { for (i = 0; i < CPU_FIELDCNT; i++) {
ullong t = bar_sz * data[i]; ullong t = bar_sz * data[i];
norm_all += data[i] = t / all; norm_all += data[i] = t / all;
frac[i] = t % all; frac[i] = t % all;
@ -298,7 +336,7 @@ static void collect_cpu(cpu_stat *s)
while (norm_all < bar_sz) { while (norm_all < bar_sz) {
unsigned max = frac[0]; unsigned max = frac[0];
int pos = 0; int pos = 0;
for (i=1; i<CPU_FIELDCNT; i++) { for (i = 1; i < CPU_FIELDCNT; i++) {
if (frac[i] > max) max = frac[i], pos = i; if (frac[i] > max) max = frac[i], pos = i;
} }
frac[pos] = 0; //avoid bumping up same value twice frac[pos] = 0; //avoid bumping up same value twice
@ -640,11 +678,9 @@ S_STAT_END(fd_stat)
static void collect_fd(fd_stat *s) static void collect_fd(fd_stat *s)
{ {
char file[4096];
ullong data[2]; ullong data[2];
readfile_z(file, sizeof(file), "/proc/sys/fs/file-nr"); if (rdval(get_file(&proc_sys_fs_filenr), "", data, 1, 2)) {
if (rdval(file, "", data, 1, 2)) {
put_question_marks(4); put_question_marks(4);
return; return;
} }
@ -702,7 +738,7 @@ static s_stat* init_time(const char *param)
static void collect_info(s_stat *s) static void collect_info(s_stat *s)
{ {
gen++; gen ^= 1;
while (s) { while (s) {
put(s->label); put(s->label);
s->collect(s); s->collect(s);
@ -714,7 +750,7 @@ static void collect_info(s_stat *s)
typedef s_stat* init_func(const char *param); typedef s_stat* init_func(const char *param);
static const char options[] = "ncmsfixptbdr"; static const char options[] = "ncmsfixptbdr";
static init_func* init_functions[] = { static init_func *const init_functions[] = {
init_if, init_if,
init_cpu, init_cpu,
init_mem, init_mem,
@ -738,10 +774,15 @@ int nmeter_main(int argc, char **argv)
s_stat *s; s_stat *s;
char *cur, *prev; char *cur, *prev;
PTR_TO_GLOBALS = xzalloc(sizeof(G));
INIT_G();
xchdir("/proc");
if (argc != 2) if (argc != 2)
bb_show_usage(); bb_show_usage();
if (open_read_close("/proc/version", buf, sizeof(buf)) > 0) if (open_read_close("version", buf, sizeof(buf)) > 0)
is26 = (strstr(buf, " 2.4.")==NULL); is26 = (strstr(buf, " 2.4.")==NULL);
// Can use argv[1] directly, but this will mess up // Can use argv[1] directly, but this will mess up
@ -750,11 +791,11 @@ int nmeter_main(int argc, char **argv)
while (1) { while (1) {
char *param, *p; char *param, *p;
prev = cur; prev = cur;
again: again:
cur = strchr(cur, '%'); cur = strchr(cur, '%');
if (!cur) if (!cur)
break; break;
if (cur[1]=='%') { // %% if (cur[1] == '%') { // %%
strcpy(cur, cur+1); strcpy(cur, cur+1);
cur++; cur++;
goto again; goto again;
@ -813,12 +854,12 @@ again:
collect_info(first); collect_info(first);
reset_outbuf(); reset_outbuf();
if (delta >= 0) { if (delta >= 0) {
gettimeofday(&tv, 0); gettimeofday(&tv, NULL);
usleep(delta > 1000000 ? 1000000 : delta - tv.tv_usec%deltanz); usleep(delta > 1000000 ? 1000000 : delta - tv.tv_usec%deltanz);
} }
while (1) { while (1) {
gettimeofday(&tv, 0); gettimeofday(&tv, NULL);
collect_info(first); collect_info(first);
put(final_str); put(final_str);
print_outbuf(); print_outbuf();
@ -831,9 +872,9 @@ again:
if (delta >= 0) { if (delta >= 0) {
int rem; int rem;
// can be commented out, will sacrifice sleep time precision a bit // can be commented out, will sacrifice sleep time precision a bit
gettimeofday(&tv, 0); gettimeofday(&tv, NULL);
if (need_seconds) if (need_seconds)
rem = delta - ((ullong)tv.tv_sec*1000000+tv.tv_usec)%deltanz; rem = delta - ((ullong)tv.tv_sec*1000000 + tv.tv_usec) % deltanz;
else else
rem = delta - tv.tv_usec%deltanz; rem = delta - tv.tv_usec%deltanz;
// Sometimes kernel wakes us up just a tiny bit earlier than asked // Sometimes kernel wakes us up just a tiny bit earlier than asked
@ -845,5 +886,5 @@ again:
} }
} }
return 0; /*return 0;*/
} }