determine frequency from cpu brand, revise code

=> move all helper functions to utils.c

tools/CMakeLists.txt

@@ -5,7 +5,7 @@ include(../cmake/HermitCore-Paths.cmake)
 
 add_compile_options(-std=c99)
 
-add_executable(proxy proxy.c uhyve.c uhyve-net.c)
+add_executable(proxy proxy.c utils.c uhyve.c uhyve-net.c)
 target_compile_options(proxy PUBLIC -pthread)
 target_link_libraries(proxy -pthread)
 

tools/proxy.c

@@ -129,33 +129,13 @@ static void exit_handler(int sig)
 
 static char* get_append_string(void)
 {
-	char line[2048];
+	uint32_t freq = get_cpufreq();
-	char* match;
+	if (freq == 0)
-	char* point;
+		return "-freq0 -proxy";
 
-	FILE* fp = fopen("/proc/cpuinfo", "r");
+	snprintf(cmdline, MAX_PATH, "\"-freq%u -proxy\"", freq);
-	if (!fp)
-		return "-freq0";
 
-	while(fgets(line, 2048, fp)) {
+	return cmdline;
-		if ((match = strstr(line, "cpu MHz")) == NULL)
-			continue;
-
-		// scan strinf for the next number
-		for(; (*match < 0x30) || (*match > 0x39); match++)
-			;
-
-		for(point = match; ((*point != '.') && (*point != '\0')); point++)
-			;
-		*point = '\0';
-
-		snprintf(cmdline, MAX_PATH, "\"-freq%s -proxy\"", match);
-		fclose(fp);
-
-		return cmdline;
-	}
-
-	return "-freq0";
 }
 
 static int env_init(char *path)

tools/proxy.h

@@ -28,6 +28,12 @@
 #ifndef __PROXY_H__
 #define __PROXY_H__
 
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <unistd.h>
+#include <stdlib.h>
 #include <stdint.h>
 
 #define HERMIT_ELFOSABI	0x42
@@ -42,4 +48,8 @@
 int uhyve_init(char *path);
 int uhyve_loop(void);
 
+// define some helper functions
+uint32_t get_cpufreq(void);
+ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset);
+
 #endif

tools/uhyve.c

@@ -32,7 +32,7 @@
  *            remove memory limit
  */
 
-#define _GNU_SOURCE
+ #define _GNU_SOURCE
 
 #include <unistd.h>
 #include <stdio.h>
@@ -288,75 +288,6 @@ static void uhyve_atexit(void)
 	close_fd(&kvm);
 }
 
-static uint32_t get_cpufreq(void)
-{
-	char line[128];
-	uint32_t freq = 0;
-	char* match;
-
-	FILE* fp = fopen("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", "r");
-	if (fp != NULL) {
-		if (fgets(line, sizeof(line), fp) != NULL) {
-			// cpuinfo_max_freq is in kHz
-			freq = (uint32_t) atoi(line) / 1000;
-		}
-
-		fclose(fp);
-	} else if( (fp = fopen("/proc/cpuinfo", "r")) ) {
-		// Resorting to /proc/cpuinfo, however on most systems this will only
-		// return the current frequency that might change over time.
-		// Currently only needed when running inside a VM
-
-		// read until we find the line indicating cpu frequency
-		while(fgets(line, sizeof(line), fp) != NULL) {
-			match = strstr(line, "cpu MHz");
-
-			if(match != NULL) {
-				// advance pointer to beginning of number
-				while( ((*match < '0') || (*match > '9')) && (*match != '\0') )
-					match++;
-
-				freq = (uint32_t) atoi(match);
-				break;
-			}
-		}
-
-		fclose(fp);
-	}
-
-	return freq;
-}
-
-static ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
-{
-	ssize_t total = 0;
-	char *p = buf;
-
-	if (count > SSIZE_MAX) {
-		errno = E2BIG;
-		return -1;
-	}
-
-	while (count > 0) {
-		ssize_t nr;
-
-		nr = pread(fd, p, count, offset);
-		if (nr == 0)
-			return total;
-		else if (nr == -1 && errno == EINTR)
-			continue;
-		else if (nr == -1)
-			return -1;
-
-		count -= nr;
-		total += nr;
-		p += nr;
-		offset += nr;
-	}
-
-	return total;
-}
-
 static int load_kernel(uint8_t* mem, char* path)
 {
 	Elf64_Ehdr hdr;

tools/utils.c

@@ -0,0 +1,171 @@
+/*
+* Copyright (c) 2017, Stefan Lankes, RWTH Aachen University
+* All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are met:
+*    * Redistributions of source code must retain the above copyright
+*      notice, this list of conditions and the following disclaimer.
+*    * Redistributions in binary form must reproduce the above copyright
+*      notice, this list of conditions and the following disclaimer in the
+*      documentation and/or other materials provided with the distribution.
+*    * Neither the name of the University nor the names of its contributors
+*      may be used to endorse or promote products derived from this
+*      software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+
+#include "proxy.h"
+
+inline static void __cpuid(uint32_t code, uint32_t* a, uint32_t* b, uint32_t* c, uint32_t* d)
+{
+	__asm volatile ("cpuid" : "=a"(*a), "=b"(*b), "=c"(*c), "=d"(*d) : "0"(code), "2"(*c));
+}
+
+// Try to determine the frequency from the CPU brand.
+// Code is derived from the manual "Intel Processor
+// Identification and the CPUID Instruction".
+static uint32_t get_frequency_from_brand(void)
+{
+	char cpu_brand[4*3*sizeof(uint32_t)+1] = {[0 ... 4*3*sizeof(uint32_t)] = 0};
+	uint32_t* bint = (uint32_t*) cpu_brand;
+	uint32_t index, multiplier = 0;
+	uint32_t cpu_freq = 0;
+	uint32_t extended;
+
+	__cpuid(0x80000000, &extended, bint+1, bint+2, bint+3);
+	if (extended < 0x80000004)
+	return 0;
+
+	__cpuid(0x80000002, bint+0, bint+1, bint+2, bint+3);
+	__cpuid(0x80000003, bint+4, bint+5, bint+6, bint+7);
+	__cpuid(0x80000004, bint+8, bint+9, bint+10, bint+11);
+
+	for(index=0; index<sizeof(cpu_brand)-2; index++)
+	{
+		if ((cpu_brand[index+1] == 'H') && (cpu_brand[index+2] == 'z'))
+		{
+			if (cpu_brand[index] == 'M')
+			multiplier = 1;
+			else if (cpu_brand[index] == 'G')
+			multiplier = 1000;
+			else if (cpu_brand[index] == 'T')
+			multiplier = 1000000;
+		}
+
+		if (multiplier > 0) {
+			uint32_t freq;
+
+			// Compute frequency (in MHz) from brand string
+			if (cpu_brand[index-3] == '.') { // If format is “x.xx”
+				freq  = (uint32_t)(cpu_brand[index-4] - '0') * multiplier;
+				freq += (uint32_t)(cpu_brand[index-2] - '0') * (multiplier / 10);
+				freq += (uint32_t)(cpu_brand[index-1] - '0') * (multiplier / 100);
+			} else { // If format is xxxx
+				freq  = (uint32_t)(cpu_brand[index-4] - '0') * 1000;
+				freq += (uint32_t)(cpu_brand[index-3] - '0') * 100;
+				freq += (uint32_t)(cpu_brand[index-2] - '0') * 10;
+				freq += (uint32_t)(cpu_brand[index-1] - '0');
+				freq *= multiplier;
+			}
+
+			return freq;
+		}
+	}
+
+	return 0;
+}
+
+uint32_t get_cpufreq(void)
+{
+	char line[128];
+	uint32_t freq = 0;
+	char* match;
+
+	freq = get_frequency_from_brand();
+	if (freq > 0)
+	return freq;
+
+	// TODO: fallback solution, on some systems is cpuinfo_max_freq the turbo frequency
+	// => wrong value
+	FILE* fp = fopen("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", "r");
+	if (fp != NULL) {
+		if (fgets(line, sizeof(line), fp) != NULL) {
+			// cpuinfo_max_freq is in kHz
+			freq = (uint32_t) atoi(line) / 1000;
+		}
+
+		fclose(fp);
+	} else if( (fp = fopen("/proc/cpuinfo", "r")) ) {
+		// Resorting to /proc/cpuinfo, however on most systems this will only
+		// return the current frequency that might change over time.
+		// Currently only needed when running inside a VM
+
+		// read until we find the line indicating cpu frequency
+		while(fgets(line, sizeof(line), fp) != NULL) {
+			match = strstr(line, "cpu MHz");
+
+			if(match != NULL) {
+				// advance pointer to beginning of number
+				while( ((*match < '0') || (*match > '9')) && (*match != '\0') )
+				match++;
+
+				freq = (uint32_t) atoi(match);
+				break;
+			}
+		}
+
+		fclose(fp);
+	}
+
+	return freq;
+}
+
+ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
+{
+	ssize_t total = 0;
+	char *p = buf;
+
+	if (count > SSIZE_MAX) {
+		errno = E2BIG;
+		return -1;
+	}
+
+	while (count > 0) {
+		ssize_t nr;
+
+		nr = pread(fd, p, count, offset);
+		if (nr == 0)
+			return total;
+		else if (nr == -1 && errno == EINTR)
+			continue;
+		else if (nr == -1)
+			return -1;
+
+		count -= nr;
+		total += nr;
+		p += nr;
+		offset += nr;
+	}
+
+	return total;
+}