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