add cpu stat

@@ -1079,6 +1079,18 @@ int SrsConfig::parse_options(int argc, char** argv)
 {
     int ret = ERROR_SUCCESS;
     
+    for (int i = 0; i < argc; i++) {
+        _argv.append(argv[i]);
+        
+        if (i < argc - 1) {
+            _argv.append(" ");
+        }
+    }
+    
+    char cwd[256];
+    getcwd(cwd, sizeof(cwd));
+    _cwd = cwd;
+    
     show_help = true;
     for (int i = 1; i < argc; i++) {
         if ((ret = parse_argv(i, argv)) != ERROR_SUCCESS) {
@@ -1239,6 +1251,16 @@ void SrsConfig::print_help(char** argv)
         argv[0], argv[0], argv[0], argv[0]);
 }
 
+string SrsConfig::get_cwd()
+{
+    return _cwd;
+}
+
+string SrsConfig::get_argv()
+{
+    return _argv;
+}
+
 bool SrsConfig::get_deamon()
 {
     srs_assert(root);

@@ -120,6 +120,8 @@ private:
     bool test_conf;
     bool show_version;
     std::string config_file;
+    std::string _argv;
+    std::string _cwd;
     SrsConfDirective* root;
     std::vector<ISrsReloadHandler*> subscribes;
 public:
@@ -143,6 +145,9 @@ private:
     virtual int parse_file(const char* filename);
     virtual int parse_argv(int& i, char** argv);
     virtual void print_help(char** argv);
+public:
+    virtual std::string         get_cwd();
+    virtual std::string         get_argv();
 // global section
 public:
     virtual SrsConfDirective*   get_root();

@@ -34,6 +34,8 @@ using namespace std;
 #include <srs_app_socket.hpp>
 #include <srs_core_autofree.hpp>
 #include <srs_app_json.hpp>
+#include <srs_app_config.hpp>
+#include <srs_kernel_utility.hpp>
 
 SrsApiRoot::SrsApiRoot()
 {
@@ -114,6 +116,8 @@ int SrsApiApi::do_process_request(SrsSocket* skt, SrsHttpMessage* req)
 SrsApiV1::SrsApiV1()
 {
     handlers.push_back(new SrsApiVersion());
+    handlers.push_back(new SrsApiSummaries());
+    handlers.push_back(new SrsApiRusages());
     handlers.push_back(new SrsApiAuthors());
 }
 
@@ -134,6 +138,9 @@ int SrsApiV1::do_process_request(SrsSocket* skt, SrsHttpMessage* req)
         << JFIELD_ERROR(ERROR_SUCCESS) << JFIELD_CONT
         << JFIELD_ORG("urls", JOBJECT_START)
             << JFIELD_STR("versions", "the version of SRS") << JFIELD_CONT
+            << JFIELD_STR("summaries", "the summary(pid, argv, pwd, cpu, mem) of SRS") << JFIELD_CONT
+            << JFIELD_STR("rusages", "the rusage of SRS") << JFIELD_CONT
+            << JFIELD_STR("proc_stats", "the /proc/self/stat of SRS") << JFIELD_CONT
             << JFIELD_STR("authors", "the primary authors and contributors")
         << JOBJECT_END
         << JOBJECT_END;
@@ -171,6 +178,89 @@ int SrsApiVersion::do_process_request(SrsSocket* skt, SrsHttpMessage* req)
     return res_json(skt, req, ss.str());
 }
 
+SrsApiSummaries::SrsApiSummaries()
+{
+}
+
+SrsApiSummaries::~SrsApiSummaries()
+{
+}
+
+bool SrsApiSummaries::can_handle(const char* path, int length, const char** /*pchild*/)
+{
+    return srs_path_equals("/summaries", path, length);
+}
+
+int SrsApiSummaries::do_process_request(SrsSocket* skt, SrsHttpMessage* req)
+{
+    std::stringstream ss;
+    
+    SrsRusage* r = srs_get_system_rusage();
+    SrsCpuSelfStat* u = srs_get_self_cpu_stat();
+    SrsCpuSystemStat* s = srs_get_system_cpu_stat();
+    
+    ss << JOBJECT_START
+        << JFIELD_ERROR(ERROR_SUCCESS) << JFIELD_CONT
+        << JFIELD_ORG("data", JOBJECT_START)
+            << JFIELD_ORG("pid", getpid()) << JFIELD_CONT
+            << JFIELD_STR("argv", _srs_config->get_argv()) << JFIELD_CONT
+            << JFIELD_STR("cwd", _srs_config->get_cwd()) << JFIELD_CONT
+            << JFIELD_ORG("rusage_ok", (r->ok? "true":"false")) << JFIELD_CONT
+            << JFIELD_ORG("self_cpu_stat_ok", (u->ok? "true":"false")) << JFIELD_CONT
+            << JFIELD_ORG("system_cpu_stat_ok", (s->ok? "true":"false")) << JFIELD_CONT
+            << JFIELD_ORG("mem_kbyte", r->r.ru_maxrss) << JFIELD_CONT
+            << JFIELD_ORG("ppid", u->ppid)
+        << JOBJECT_END
+        << JOBJECT_END;
+    
+    return res_json(skt, req, ss.str());
+}
+
+SrsApiRusages::SrsApiRusages()
+{
+}
+
+SrsApiRusages::~SrsApiRusages()
+{
+}
+
+bool SrsApiRusages::can_handle(const char* path, int length, const char** /*pchild*/)
+{
+    return srs_path_equals("/rusages", path, length);
+}
+
+int SrsApiRusages::do_process_request(SrsSocket* skt, SrsHttpMessage* req)
+{
+    std::stringstream ss;
+    
+    SrsRusage* r = srs_get_system_rusage();
+    
+    ss << JOBJECT_START
+        << JFIELD_ERROR(ERROR_SUCCESS) << JFIELD_CONT
+        << JFIELD_ORG("data", JOBJECT_START)
+            << JFIELD_ORG("rusage_ok", (r->ok? "true":"false")) << JFIELD_CONT
+            << JFIELD_ORG("ru_utime", r->r.ru_utime.tv_sec) << JFIELD_CONT
+            << JFIELD_ORG("ru_stime", r->r.ru_stime.tv_sec) << JFIELD_CONT
+            << JFIELD_ORG("ru_maxrss", r->r.ru_maxrss) << JFIELD_CONT
+            << JFIELD_ORG("ru_ixrss", r->r.ru_ixrss) << JFIELD_CONT
+            << JFIELD_ORG("ru_idrss", r->r.ru_idrss) << JFIELD_CONT
+            << JFIELD_ORG("ru_isrss", r->r.ru_isrss) << JFIELD_CONT
+            << JFIELD_ORG("ru_minflt", r->r.ru_minflt) << JFIELD_CONT
+            << JFIELD_ORG("ru_majflt", r->r.ru_majflt) << JFIELD_CONT
+            << JFIELD_ORG("ru_nswap", r->r.ru_nswap) << JFIELD_CONT
+            << JFIELD_ORG("ru_inblock", r->r.ru_inblock) << JFIELD_CONT
+            << JFIELD_ORG("ru_oublock", r->r.ru_oublock) << JFIELD_CONT
+            << JFIELD_ORG("ru_msgsnd", r->r.ru_msgsnd) << JFIELD_CONT
+            << JFIELD_ORG("ru_msgrcv", r->r.ru_msgrcv) << JFIELD_CONT
+            << JFIELD_ORG("ru_nsignals", r->r.ru_nsignals) << JFIELD_CONT
+            << JFIELD_ORG("ru_nvcsw", r->r.ru_nvcsw) << JFIELD_CONT
+            << JFIELD_ORG("ru_nivcsw", r->r.ru_nivcsw)
+        << JOBJECT_END
+        << JOBJECT_END;
+    
+    return res_json(skt, req, ss.str());
+}
+
 SrsApiAuthors::SrsApiAuthors()
 {
 }

@@ -87,6 +87,28 @@ protected:
     virtual int do_process_request(SrsSocket* skt, SrsHttpMessage* req);
 };
 
+class SrsApiSummaries : public SrsHttpHandler
+{
+public:
+    SrsApiSummaries();
+    virtual ~SrsApiSummaries();
+public:
+    virtual bool can_handle(const char* path, int length, const char** pchild);
+protected:
+    virtual int do_process_request(SrsSocket* skt, SrsHttpMessage* req);
+};
+
+class SrsApiRusages : public SrsHttpHandler
+{
+public:
+    SrsApiRusages();
+    virtual ~SrsApiRusages();
+public:
+    virtual bool can_handle(const char* path, int length, const char** pchild);
+protected:
+    virtual int do_process_request(SrsSocket* skt, SrsHttpMessage* req);
+};
+
 class SrsApiAuthors : public SrsHttpHandler
 {
 public:

@@ -46,7 +46,21 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #endif
 
 #define SERVER_LISTEN_BACKLOG 512
-#define SRS_SYS_TIME_RESOLUTION_MS 500
+
+// system interval
+#define SRS_SYS_CYCLE_INTERVAL 100
+
+// update time interval:
+//      SRS_SYS_CYCLE_INTERVAL * SRS_SYS_TIME_RESOLUTION_MS_TIMES
+#define SRS_SYS_TIME_RESOLUTION_MS_TIMES 3
+
+// update rusage interval:
+//      SRS_SYS_CYCLE_INTERVAL * SRS_SYS_RUSAGE_RESOLUTION_TIMES
+#define SRS_SYS_RUSAGE_RESOLUTION_TIMES 15
+
+// update rusage interval:
+//      SRS_SYS_CYCLE_INTERVAL * SRS_SYS_CPU_STAT_RESOLUTION_TIMES
+#define SRS_SYS_CPU_STAT_RESOLUTION_TIMES 15
 
 SrsListener::SrsListener(SrsServer* server, SrsListenerType type)
 {
@@ -393,10 +407,15 @@ int SrsServer::cycle()
 {
     int ret = ERROR_SUCCESS;
     
+    // find the max loop
+    int max = srs_max(0, SRS_SYS_TIME_RESOLUTION_MS_TIMES);
+    max = srs_max(max, SRS_SYS_RUSAGE_RESOLUTION_TIMES);
+    max = srs_max(max, SRS_SYS_CPU_STAT_RESOLUTION_TIMES);
+    
     // the deamon thread, update the time cache
     while (true) {
-        st_usleep(SRS_SYS_TIME_RESOLUTION_MS * 1000);
-        srs_update_system_time_ms();
+        for (int i = 1; i < max + 1; i++) {
+            st_usleep(SRS_SYS_CYCLE_INTERVAL * 1000);
         
 // for gperf heap checker,
 // @see: research/gperftools/heap-checker/heap_checker.cc
@@ -404,20 +423,32 @@ int SrsServer::cycle()
 // but, if gperf, use reload to ensure main return normally,
 // because directly exit will cause core-dump.
 #ifdef SRS_AUTO_GPERF_MC
-        if (signal_gmc_stop) {
-            break;
-        }
+            if (signal_gmc_stop) {
+                break;
+            }
 #endif
         
-        if (signal_reload) {
-            signal_reload = false;
-            srs_info("get signal reload, to reload the config.");
+            if (signal_reload) {
+                signal_reload = false;
+                srs_info("get signal reload, to reload the config.");
+                
+                if ((ret = _srs_config->reload()) != ERROR_SUCCESS) {
+                    srs_error("reload config failed. ret=%d", ret);
+                    return ret;
+                }
+                srs_trace("reload config success.");
+            }
             
-            if ((ret = _srs_config->reload()) != ERROR_SUCCESS) {
-                srs_error("reload config failed. ret=%d", ret);
-                return ret;
+            // update the cache time or rusage.
+            if (i == SRS_SYS_TIME_RESOLUTION_MS_TIMES) {
+                srs_update_system_time_ms();
+            }
+            if (i == SRS_SYS_RUSAGE_RESOLUTION_TIMES) {
+                srs_update_system_rusage();
+            }
+            if (i == SRS_SYS_CPU_STAT_RESOLUTION_TIMES) {
+                srs_update_system_cpu_stat();
             }
-            srs_trace("reload config success.");
         }
     }
 

@@ -57,3 +57,116 @@ void srs_update_system_time_ms()
     
     _srs_system_time_us_cache = now_us;
 }
+
+static SrsRusage _srs_system_rusage;
+
+SrsRusage::SrsRusage()
+{
+    ok = false;
+    memset(&r, 0, sizeof(rusage));
+}
+
+SrsRusage* srs_get_system_rusage()
+{
+    return &_srs_system_rusage;
+}
+
+void srs_update_system_rusage()
+{
+    if (getrusage(RUSAGE_SELF, &_srs_system_rusage.r) < 0) {
+        srs_warn("getrusage failed, ignore");
+        return;
+    }
+    
+    _srs_system_rusage.ok = true;
+}
+
+static SrsCpuSelfStat _srs_system_cpu_self_stat;
+static SrsCpuSystemStat _srs_system_cpu_system_stat;
+
+SrsCpuSelfStat::SrsCpuSelfStat()
+{
+    ok = false;
+}
+
+SrsCpuSystemStat::SrsCpuSystemStat()
+{
+    ok = false;
+}
+
+SrsCpuSelfStat* srs_get_self_cpu_stat()
+{
+    return &_srs_system_cpu_self_stat;
+}
+
+SrsCpuSystemStat* srs_get_system_cpu_stat()
+{
+    return &_srs_system_cpu_system_stat;
+}
+
+void srs_update_system_cpu_stat()
+{
+    // system cpu stat
+    if (true) {
+        FILE* f = fopen("/proc/stat", "r");
+        if (f == NULL) {
+            srs_warn("open system cpu stat failed, ignore");
+            return;
+        }
+        
+        SrsCpuSystemStat& r = _srs_system_cpu_system_stat;
+        for (;;) {
+            int ret = fscanf(f, "%4s %lu %lu %lu %lu %lu "
+                "%lu %lu %lu %lu\n", 
+                r.label, &r.user, &r.nice, &r.sys, &r.idle, &r.iowait,
+                &r.irq, &r.softirq, &r.steal, &r.guest);
+            r.ok = false;
+            
+            if (ret == EOF) {
+                break;
+            }
+            
+            if (strcmp("cpu", r.label) == 0) {
+                r.ok = true;
+                break;
+            }
+        }
+        
+        fclose(f);
+    }
+    
+    // self cpu stat
+    if (true) {
+        FILE* f = fopen("/proc/self/stat", "r");
+        if (f == NULL) {
+            srs_warn("open self cpu stat failed, ignore");
+            return;
+        }
+        
+        SrsCpuSelfStat& r = _srs_system_cpu_self_stat;
+        int ret = fscanf(f, "%d %32s %c %d %d %d %d "
+            "%d %u %lu %lu %lu %lu "
+            "%lu %lu %ld %ld %ld %ld "
+            "%ld %ld %llu %lu %ld "
+            "%lu %lu %lu %lu %lu "
+            "%lu %lu %lu %lu %lu "
+            "%lu %lu %lu %d %d "
+            "%u %u %llu "
+            "%lu %ld", 
+            &r.pid, r.comm, &r.state, &r.ppid, &r.pgrp, &r.session, &r.tty_nr,
+            &r.tpgid, &r.flags, &r.minflt, &r.cminflt, &r.majflt, &r.cmajflt,
+            &r.utime, &r.stime, &r.cutime, &r.cstime, &r.priority, &r.nice,
+            &r.num_threads, &r.itrealvalue, &r.starttime, &r.vsize, &r.rss,
+            &r.rsslim, &r.startcode, &r.endcode, &r.startstack, &r.kstkesp,
+            &r.kstkeip, &r.signal, &r.blocked, &r.sigignore, &r.sigcatch,
+            &r.wchan, &r.nswap, &r.cnswap, &r.exit_signal, &r.processor,
+            &r.rt_priority, &r.policy, &r.delayacct_blkio_ticks, 
+            &r.guest_time, &r.cguest_time);
+            
+        if (ret >= 0) {
+            r.ok = true;
+        }
+        
+        fclose(f);
+    }
+}

@@ -30,9 +30,222 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_core.hpp>
 
+#include <sys/resource.h>
+
 // get current system time in ms, use cache to avoid performance problem
 extern int64_t srs_get_system_time_ms();
 // the deamon st-thread will update it.
 extern void srs_update_system_time_ms();
 
+// @see: man getrusage
+struct SrsRusage
+{
+    bool ok;
+    rusage r;
+    
+    SrsRusage();
+};
+
+// get system rusage, use cache to avoid performance problem.
+extern SrsRusage* srs_get_system_rusage();
+// the deamon st-thread will update it.
+extern void srs_update_system_rusage();
+
+// @see: man 5 proc, /proc/[pid]/stat
+struct SrsCpuSelfStat
+{
+    // whether the data is ok.
+    bool ok;
+    
+    // pid %d      The process ID.
+    int pid;
+    // comm %s     The  filename  of  the  executable,  in parentheses. This is visible whether or not the executable is
+    //             swapped out.
+    char comm[32];
+    // state %c    One character from the string "RSDZTW" where R is running, S is sleeping in an interruptible  wait,  D
+    //             is  waiting in uninterruptible disk sleep, Z is zombie, T is traced or stopped (on a signal), and W is
+    //             paging.
+    char state;
+    // ppid %d     The PID of the parent.
+    int ppid;
+    // pgrp %d     The process group ID of the process.
+    int pgrp;
+    // session %d  The session ID of the process.
+    int session;
+    // tty_nr %d   The controlling terminal of the process.  (The minor device number is contained in the combination  of
+    //             bits 31 to 20 and 7 to 0; the major device number is in bits 15 t0 8.)
+    int tty_nr;
+    // tpgid %d    The ID of the foreground process group of the controlling terminal of the process.
+    int tpgid;
+    // flags %u (%lu before Linux 2.6.22)
+    //             The  kernel  flags  word  of  the process.  For bit meanings, see the PF_* defines in <linux/sched.h>.
+    //             Details depend on the kernel version.
+    unsigned int flags;
+    // minflt %lu  The number of minor faults the process has made which have not required loading  a  memory  page  from
+    //             disk.
+    unsigned long minflt;
+    // cminflt %lu The number of minor faults that the process’s waited-for children have made.
+    unsigned long cminflt;
+    // majflt %lu  The number of major faults the process has made which have required loading a memory page from disk.
+    unsigned long majflt;
+    // cmajflt %lu The number of major faults that the process’s waited-for children have made.
+    unsigned long cmajflt;
+    // utime %lu   Amount  of  time that this process has been scheduled in user mode, measured in clock ticks (divide by
+    //             sysconf(_SC_CLK_TCK).  This includes guest time, guest_time (time spent running  a  virtual  CPU,  see
+    //             below),  so  that  applications  that are not aware of the guest time field do not lose that time from
+    //             their calculations.
+    unsigned long utime;
+    // stime %lu   Amount of time that this process has been scheduled in kernel mode, measured in clock ticks (divide by
+    //             sysconf(_SC_CLK_TCK).
+    unsigned long stime;
+    // cutime %ld  Amount  of  time that this process’s waited-for children have been scheduled in user mode, measured in
+    //             clock ticks (divide  by  sysconf(_SC_CLK_TCK).   (See  also  times(2).)   This  includes  guest  time,
+    //             cguest_time (time spent running a virtual CPU, see below).
+    long cutime;
+    // cstime %ld  Amount of time that this process’s waited-for children have been scheduled in kernel mode, measured in
+    //             clock ticks (divide by sysconf(_SC_CLK_TCK).
+    long cstime;
+    // priority %ld
+    //          (Explanation for Linux 2.6) For processes running a real-time scheduling  policy  (policy  below;  see
+    //          sched_setscheduler(2)),  this  is the negated scheduling priority, minus one; that is, a number in the
+    //          range -2 to -100, corresponding to real-time priorities 1 to 99.  For processes running under  a  non-
+    //          real-time scheduling policy, this is the raw nice value (setpriority(2)) as represented in the kernel.
+    //          The kernel stores nice values as numbers in the range 0 (high) to 39 (low), corresponding to the user-
+    //          visible nice range of -20 to 19.
+    //
+    //          Before Linux 2.6, this was a scaled value based on the scheduler weighting given to this process.
+    long priority;
+    // nice %ld    The nice value (see setpriority(2)), a value in the range 19 (low priority) to -20 (high priority).
+    long nice;
+    // num_threads %ld
+    //          Number  of threads in this process (since Linux 2.6).  Before kernel 2.6, this field was hard coded to
+    //          0 as a placeholder for an earlier removed field.
+    long num_threads;
+    // itrealvalue %ld
+    //          The time in jiffies before the next SIGALRM is sent to the process due to an  interval  timer.   Since
+    //          kernel 2.6.17, this field is no longer maintained, and is hard coded as 0.    
+    long itrealvalue;
+    // starttime %llu (was %lu before Linux 2.6)
+    //          The time in jiffies the process started after system boot.
+    long long starttime;
+    // vsize %lu   Virtual memory size in bytes.
+    unsigned long vsize;
+    // rss %ld     Resident Set Size: number of pages the process has in real memory.  This is just the pages which count
+    //             towards text, data, or stack space.  This does not include pages which have not been demand-loaded in,
+    //             or which are swapped out.
+    long rss;
+    // rsslim %lu  Current  soft limit in bytes on the rss of the process; see the description of RLIMIT_RSS in getprior-
+    //             ity(2).
+    unsigned long rsslim;
+    // startcode %lu
+    //             The address above which program text can run.
+    unsigned long startcode;
+    // endcode %lu The address below which program text can run.
+    unsigned long endcode;
+    // startstack %lu
+    //             The address of the start (i.e., bottom) of the stack.
+    unsigned long startstack;
+    // kstkesp %lu The current value of ESP (stack pointer), as found in the kernel stack page for the process.
+    unsigned long kstkesp;
+    // kstkeip %lu The current EIP (instruction pointer).
+    unsigned long kstkeip;
+    // signal %lu  The bitmap of pending signals, displayed as a decimal number.  Obsolete, because it does  not  provide
+    //             information on real-time signals; use /proc/[pid]/status instead.
+    unsigned long signal;
+    // blocked %lu The  bitmap  of blocked signals, displayed as a decimal number.  Obsolete, because it does not provide
+    //             information on real-time signals; use /proc/[pid]/status instead.
+    unsigned long blocked;
+    // sigignore %lu
+    //             The bitmap of ignored signals, displayed as a decimal number.  Obsolete, because it does  not  provide
+    //             information on real-time signals; use /proc/[pid]/status instead.
+    unsigned long sigignore;
+    // sigcatch %lu
+    //             The  bitmap  of  caught signals, displayed as a decimal number.  Obsolete, because it does not provide
+    //             information on real-time signals; use /proc/[pid]/status instead.
+    unsigned long sigcatch;
+    // wchan %lu   This is the "channel" in which the process is waiting.  It is the address of a system call, and can be
+    //             looked  up in a namelist if you need a textual name.  (If you have an up-to-date /etc/psdatabase, then
+    //             try ps -l to see the WCHAN field in action.)
+    unsigned long wchan;
+    // nswap %lu   Number of pages swapped (not maintained).
+    unsigned long nswap;
+    // cnswap %lu  Cumulative nswap for child processes (not maintained).
+    unsigned long cnswap;
+    // exit_signal %d (since Linux 2.1.22)
+    //             Signal to be sent to parent when we die.
+    int exit_signal;
+    // processor %d (since Linux 2.2.8)
+    //             CPU number last executed on.
+    int processor;
+    // rt_priority %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
+    //             Real-time scheduling priority, a number in the range 1 to 99 for processes scheduled under a real-time
+    //             policy, or 0, for non-real-time processes (see sched_setscheduler(2)).
+    unsigned int rt_priority;
+    // policy %u (since Linux 2.5.19; was %lu before Linux 2.6.22)
+    //             Scheduling policy (see sched_setscheduler(2)).  Decode using the SCHED_* constants in linux/sched.h.
+    unsigned int policy;
+    // delayacct_blkio_ticks %llu (since Linux 2.6.18)
+    //             Aggregated block I/O delays, measured in clock ticks (centiseconds).
+    unsigned long long delayacct_blkio_ticks;
+    // guest_time %lu (since Linux 2.6.24)
+    //             Guest time of the process (time spent running a virtual CPU for a guest operating system), measured in
+    //             clock ticks (divide by sysconf(_SC_CLK_TCK).
+    unsigned long guest_time;
+    // cguest_time %ld (since Linux 2.6.24)
+    //             Guest time of the process’s children, measured in clock ticks (divide by sysconf(_SC_CLK_TCK).
+    long cguest_time;
+    
+    SrsCpuSelfStat();
+};
+
+// @see: man 5 proc, /proc/stat
+struct SrsCpuSystemStat
+{
+    // whether the data is ok.
+    bool ok;
+    
+    // always be cpu
+    char label[32];
+    
+    //The amount of time, measured in units  of  USER_HZ  (1/100ths  of  a  second  on  most  architectures,  use
+    // sysconf(_SC_CLK_TCK)  to  obtain  the  right value)
+    //
+    // the system spent in user mode, 
+    unsigned long user;
+    // user mode with low priority (nice), 
+    unsigned long nice;
+    // system mode, 
+    unsigned long sys;
+    // and the idle task, respectively.
+    unsigned long idle;
+
+    // In  Linux 2.6 this line includes three additional columns:
+    //
+    // iowait - time waiting for I/O to complete (since 2.5.41);
+    unsigned long iowait;
+    // irq - time servicing interrupts (since 2.6.0-test4); 
+    unsigned long irq;
+    // softirq  -  time  servicing  softirqs  (since 2.6.0-test4).
+    unsigned long softirq;
+    
+    // Since  Linux 2.6.11, there is an eighth column,
+    // steal - stolen time, which is the time spent in other oper-
+    // ating systems when running in a virtualized environment
+    unsigned long steal;
+    
+    // Since Linux 2.6.24, there is a ninth column, 
+    // guest, which is the time spent running a virtual CPU for guest
+    // operating systems under the control of the Linux kernel.
+    unsigned long guest;
+
+    SrsCpuSystemStat();
+};
+
+// get system cpu stat, use cache to avoid performance problem.
+extern SrsCpuSelfStat* srs_get_self_cpu_stat();
+// get system cpu stat, use cache to avoid performance problem.
+extern SrsCpuSystemStat* srs_get_system_cpu_stat();
+// the deamon st-thread will update it.
+extern void srs_update_system_cpu_stat();
+
 #endif