From 5defa9c7b07db3e8c0aeffc4d90cda24a96f705c Mon Sep 17 00:00:00 2001
From: VelocityRa <makren67@gmail.com>
Date: Thu, 24 May 2018 22:20:13 +0300
Subject: [PATCH] util: Class for getting overall CPU usage and thread count

---
 Utilities/CPUStats.h | 157 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 Utilities/CPUStats.h

diff --git a/Utilities/CPUStats.h b/Utilities/CPUStats.h
new file mode 100644
index 0000000000..f839235192
--- /dev/null
+++ b/Utilities/CPUStats.h
@@ -0,0 +1,157 @@
+#pragma once
+
+#include <Utilities/types.h>
+
+#ifdef _WIN32
+#include "windows.h"
+#include "tlhelp32.h"
+#else
+#include "dirent.h"
+#include "stdlib.h"
+#include "stdio.h"
+#include "string.h"
+#include "sys/times.h"
+#include "sys/types.h"
+#endif
+
+class CPUStats
+{
+#ifdef _WIN32
+	HANDLE m_self;
+	using time_type = ULARGE_INTEGER;
+#else
+	using time_type = clock_t;
+#endif
+
+private:
+	s32 m_num_processors;
+	time_type m_last_cpu, m_sys_cpu, m_usr_cpu;
+
+public:
+	CPUStats()
+	{
+#ifdef _WIN32
+		SYSTEM_INFO sysInfo;
+		FILETIME ftime, fsys, fuser;
+
+		GetSystemInfo(&sysInfo);
+		m_num_processors = sysInfo.dwNumberOfProcessors;
+
+		GetSystemTimeAsFileTime(&ftime);
+		memcpy(&m_last_cpu, &ftime, sizeof(FILETIME));
+
+		m_self = GetCurrentProcess();
+		GetProcessTimes(m_self, &ftime, &ftime, &fsys, &fuser);
+		memcpy(&m_sys_cpu, &fsys, sizeof(FILETIME));
+		memcpy(&m_usr_cpu, &fuser, sizeof(FILETIME));
+#else
+		FILE* file;
+		struct tms timeSample;
+		char line[128];
+
+		m_last_cpu = times(&timeSample);
+		m_sys_cpu  = timeSample.tms_stime;
+		m_usr_cpu  = timeSample.tms_utime;
+
+		file             = fopen("/proc/cpuinfo", "r");
+		m_num_processors = 0;
+		while (fgets(line, 128, file) != NULL)
+		{
+			if (strncmp(line, "processor", 9) == 0)
+				m_num_processors++;
+		}
+		fclose(file);
+#endif
+	}
+
+	double get_usage()
+	{
+#ifdef _WIN32
+		FILETIME ftime, fsys, fusr;
+		ULARGE_INTEGER now, sys, usr;
+
+		GetSystemTimeAsFileTime(&ftime);
+		memcpy(&now, &ftime, sizeof(FILETIME));
+
+		GetProcessTimes(m_self, &ftime, &ftime, &fsys, &fusr);
+		memcpy(&sys, &fsys, sizeof(FILETIME));
+		memcpy(&usr, &fusr, sizeof(FILETIME));
+		double percent = (sys.QuadPart - m_sys_cpu.QuadPart) + (usr.QuadPart - m_usr_cpu.QuadPart);
+		percent /= (now.QuadPart - m_last_cpu.QuadPart);
+		percent /= m_num_processors;
+
+		m_last_cpu = now;
+		m_usr_cpu  = usr;
+		m_sys_cpu  = sys;
+
+		return std::clamp(percent * 100, 0.0, 100.0);
+#else
+		struct tms timeSample;
+		clock_t now;
+		double percent;
+
+		now = times(&timeSample);
+		if (now <= m_last_cpu || timeSample.tms_stime < m_sys_cpu || timeSample.tms_utime < m_usr_cpu)
+		{
+			// Overflow detection. Just skip this value.
+			percent = -1.0;
+		}
+		else
+		{
+			percent = (timeSample.tms_stime - m_sys_cpu) + (timeSample.tms_utime - m_usr_cpu);
+			percent /= (now - m_last_cpu);
+			percent /= m_num_processors;
+			percent *= 100;
+		}
+		m_last_cpu = now;
+		m_sys_cpu  = timeSample.tms_stime;
+		m_usr_cpu  = timeSample.tms_utime;
+
+		return percent;
+#endif
+	}
+
+	static u32 get_thread_count()
+	{
+#ifdef _WIN32
+		// first determine the id of the current process
+		DWORD const id = GetCurrentProcessId();
+
+		// then get a process list snapshot.
+		HANDLE const snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPALL, 0);
+
+		// initialize the process entry structure.
+		PROCESSENTRY32 entry = {0};
+		entry.dwSize         = sizeof(entry);
+
+		// get the first process info.
+		BOOL ret = true;
+		ret      = Process32First(snapshot, &entry);
+		while (ret && entry.th32ProcessID != id)
+		{
+			ret = Process32Next(snapshot, &entry);
+		}
+		CloseHandle(snapshot);
+		return ret ? entry.cntThreads : 0;
+#else
+		u32 thread_count{0};
+
+		DIR* proc_dir = opendir("/proc/self/task");
+		if (proc_dir)
+		{
+			// proc available, iterate through tasks and count them
+			struct dirent* entry;
+			while ((entry = readdir(proc_dir)) != NULL)
+			{
+				if (entry->d_name[0] == '.')
+					continue;
+
+				++thread_count;
+			}
+
+			closedir(proc_dir);
+		}
+		return thread_count;
+#endif
+	}
+};