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Use sysfs to gather host topology, in place of

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/proc/cpuinfo

Libvirt at present depends on /proc/cpuinfo to gather host
details such as CPUs, cores, threads, etc. This is an architecture-
dependent approach. An alternative is to use 'Sysfs', which provides
a platform-agnostic interface to parse host CPU topology.

Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
This commit is contained in:
Prerna Saxena 2011-10-03 05:45:30 -07:00 committed by Stefan Berger
parent dbe5eb2d3a
commit f99b3b4b50
1 changed files with 61 additions and 83 deletions
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144
src/nodeinfo.c
View File

@ -30,6 +30,7 @@
#include <errno.h> #include <errno.h>
#include <dirent.h> #include <dirent.h>
#include <sys/utsname.h> #include <sys/utsname.h>
#include <sched.h>
#if HAVE_NUMACTL #if HAVE_NUMACTL
# define NUMA_VERSION1_COMPATIBILITY 1 # define NUMA_VERSION1_COMPATIBILITY 1
@ -67,8 +68,8 @@
/* NB, this is not static as we need to call it from the testsuite */ /* NB, this is not static as we need to call it from the testsuite */
int linuxNodeInfoCPUPopulate(FILE *cpuinfo, int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
virNodeInfoPtr nodeinfo, char *sysfs_cpudir,
bool need_hyperthreads); virNodeInfoPtr nodeinfo);
static int linuxNodeGetCPUStats(FILE *procstat, static int linuxNodeGetCPUStats(FILE *procstat,
int cpuNum, int cpuNum,
@ -79,8 +80,9 @@ static int linuxNodeGetMemoryStats(FILE *meminfo,
virNodeMemoryStatsPtr params, virNodeMemoryStatsPtr params,
int *nparams); int *nparams);
static char sysfs_path[1024];
/* Return the positive decimal contents of the given /* Return the positive decimal contents of the given
* CPU_SYS_PATH/cpu%u/FILE, or -1 on error. If MISSING_OK and the * (*sysfs_path)/cpu%u/FILE, or -1 on error. If MISSING_OK and the
* file could not be found, return 1 instead of an error; this is * file could not be found, return 1 instead of an error; this is
* because some machines cannot hot-unplug cpu0, or because * because some machines cannot hot-unplug cpu0, or because
* hot-unplugging is disabled. */ * hot-unplugging is disabled. */
@ -93,7 +95,7 @@ get_cpu_value(unsigned int cpu, const char *file, bool missing_ok)
char value_str[INT_BUFSIZE_BOUND(value)]; char value_str[INT_BUFSIZE_BOUND(value)];
char *tmp; char *tmp;
if (virAsprintf(&path, CPU_SYS_PATH "/cpu%u/%s", cpu, file) < 0) { if (virAsprintf(&path, "%s/cpu%u/%s", sysfs_path, cpu, file) < 0) {
virReportOOMError(); virReportOOMError();
return -1; return -1;
} }
@ -125,7 +127,7 @@ cleanup:
return value; return value;
} }
/* Check if CPU is online via CPU_SYS_PATH/cpu%u/online. Return 1 if online, /* Check if CPU is online via sysfs_path/cpu%u/online. Return 1 if online,
0 if offline, and -1 on error. */ 0 if offline, and -1 on error. */
static int static int
cpu_online(unsigned int cpu) cpu_online(unsigned int cpu)
@ -141,8 +143,8 @@ static unsigned long count_thread_siblings(unsigned int cpu)
char str[1024]; char str[1024];
int i; int i;
if (virAsprintf(&path, CPU_SYS_PATH "/cpu%u/topology/thread_siblings", if (virAsprintf(&path, "%s/cpu%u/topology/thread_siblings",
cpu) < 0) { sysfs_path, cpu) < 0) {
virReportOOMError(); virReportOOMError();
return 0; return 0;
} }
@ -191,23 +193,27 @@ static int parse_socket(unsigned int cpu)
return ret; return ret;
} }
static int parse_core(unsigned int cpu)
{
return get_cpu_value(cpu, "topology/core_id", false);
}
int linuxNodeInfoCPUPopulate(FILE *cpuinfo, int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
virNodeInfoPtr nodeinfo, char *sysfs_cpudir,
bool need_hyperthreads) virNodeInfoPtr nodeinfo)
{ {
char line[1024]; char line[1024];
DIR *cpudir = NULL; DIR *cpudir = NULL;
struct dirent *cpudirent = NULL; struct dirent *cpudirent = NULL;
unsigned int cpu; unsigned int cpu;
unsigned long cur_threads; unsigned long core, socket, cur_threads;
int socket; cpu_set_t core_mask;
unsigned long long socket_mask = 0; cpu_set_t socket_mask;
unsigned int remaining;
int online; int online;
nodeinfo->cpus = 0; nodeinfo->cpus = 0;
nodeinfo->mhz = 0; nodeinfo->mhz = 0;
nodeinfo->cores = 1; nodeinfo->cores = 0;
nodeinfo->nodes = 1; nodeinfo->nodes = 1;
# if HAVE_NUMACTL # if HAVE_NUMACTL
@ -215,26 +221,20 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
nodeinfo->nodes = numa_max_node() + 1; nodeinfo->nodes = numa_max_node() + 1;
# endif # endif
if (!virStrcpyStatic(sysfs_path, sysfs_cpudir)) {
virReportSystemError(errno, _("cannot copy %s"), sysfs_cpudir);
return -1;
}
/* NB: It is impossible to fill our nodes, since cpuinfo /* NB: It is impossible to fill our nodes, since cpuinfo
* has no knowledge of NUMA nodes */ * has no knowledge of NUMA nodes */
/* NOTE: hyperthreads are ignored here; they are parsed out of /sys */ /* NOTE: hyperthreads are ignored here; they are parsed out of /sys */
while (fgets(line, sizeof(line), cpuinfo) != NULL) { while (fgets(line, sizeof(line), cpuinfo) != NULL) {
char *buf = line; char *buf = line;
if (STRPREFIX(buf, "processor")) { /* aka a single logical CPU */
buf += 9;
while (*buf && c_isspace(*buf))
buf++;
if (*buf != ':') {
nodeReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("parsing cpuinfo processor"));
return -1;
}
nodeinfo->cpus++;
# if defined(__x86_64__) || \ # if defined(__x86_64__) || \
defined(__amd64__) || \ defined(__amd64__) || \
defined(__i386__) defined(__i386__)
} else if (STRPREFIX(buf, "cpu MHz")) { if (STRPREFIX(buf, "cpu MHz")) {
char *p; char *p;
unsigned int ui; unsigned int ui;
buf += 9; buf += 9;
@ -249,24 +249,9 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
/* Accept trailing fractional part. */ /* Accept trailing fractional part. */
&& (*p == '\0' || *p == '.' || c_isspace(*p))) && (*p == '\0' || *p == '.' || c_isspace(*p)))
nodeinfo->mhz = ui; nodeinfo->mhz = ui;
} else if (STRPREFIX(buf, "cpu cores")) { /* aka cores */
char *p;
unsigned int id;
buf += 9;
while (*buf && c_isspace(*buf))
buf++;
if (*buf != ':' || !buf[1]) {
nodeReportError(VIR_ERR_INTERNAL_ERROR,
_("parsing cpuinfo cpu cores %c"), *buf);
return -1;
}
if (virStrToLong_ui(buf+1, &p, 10, &id) == 0
&& (*p == '\0' || c_isspace(*p))
&& id > nodeinfo->cores)
nodeinfo->cores = id;
# elif defined(__powerpc__) || \ # elif defined(__powerpc__) || \
defined(__powerpc64__) defined(__powerpc64__)
} else if (STRPREFIX(buf, "clock")) { if (STRPREFIX(buf, "clock")) {
char *p; char *p;
unsigned int ui; unsigned int ui;
buf += 5; buf += 5;
@ -281,53 +266,30 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
/* Accept trailing fractional part. */ /* Accept trailing fractional part. */
&& (*p == '\0' || *p == '.' || c_isspace(*p))) && (*p == '\0' || *p == '.' || c_isspace(*p)))
nodeinfo->mhz = ui; nodeinfo->mhz = ui;
# elif defined(__s390__) || \
defined(__s390x__)
} else if (STRPREFIX(buf, "# processors")) {
char *p;
unsigned int ui;
buf += 12;
while (*buf && c_isspace(*buf))
buf++;
if (*buf != ':' || !buf[1]) {
nodeReportError(VIR_ERR_INTERNAL_ERROR,
_("parsing number of processors %c"), *buf);
return -1;
}
if (virStrToLong_ui(buf+1, &p, 10, &ui) == 0
&& (*p == '\0' || c_isspace(*p)))
nodeinfo->cpus = ui;
/* No other interesting infos are available in /proc/cpuinfo. /* No other interesting infos are available in /proc/cpuinfo.
* However, there is a line identifying processor's version, * However, there is a line identifying processor's version,
* identification and machine, but we don't want it to be caught * identification and machine, but we don't want it to be caught
* and parsed in next iteration, because it is not in expected * and parsed in next iteration, because it is not in expected
* format and thus lead to error. */ * format and thus lead to error. */
break;
# else # else
# warning Parser for /proc/cpuinfo needs to be adapted for your architecture # warning Parser for /proc/cpuinfo needs to be adapted for your architecture
# endif # endif
} }
} }
if (!nodeinfo->cpus) { /* OK, we've parsed clock speed out of /proc/cpuinfo. Get the core, socket
nodeReportError(VIR_ERR_INTERNAL_ERROR, * thread and topology information from /sys
"%s", _("no cpus found"));
return -1;
}
if (!need_hyperthreads)
return 0;
/* OK, we've parsed what we can out of /proc/cpuinfo. Get the socket
* and thread information from /sys
*/ */
remaining = nodeinfo->cpus; cpudir = opendir(sysfs_cpudir);
cpudir = opendir(CPU_SYS_PATH);
if (cpudir == NULL) { if (cpudir == NULL) {
virReportSystemError(errno, _("cannot opendir %s"), CPU_SYS_PATH); virReportSystemError(errno, _("cannot opendir %s"), sysfs_cpudir);
return -1; return -1;
} }
while ((errno = 0), remaining && (cpudirent = readdir(cpudir))) {
CPU_ZERO(&core_mask);
CPU_ZERO(&socket_mask);
while ((cpudirent = readdir(cpudir))) {
if (sscanf(cpudirent->d_name, "cpu%u", &cpu) != 1) if (sscanf(cpudirent->d_name, "cpu%u", &cpu) != 1)
continue; continue;
@ -338,15 +300,19 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
} }
if (!online) if (!online)
continue; continue;
remaining--; nodeinfo->cpus++;
socket = parse_socket(cpu); /* Parse core */
if (socket < 0) { core = parse_core(cpu);
closedir(cpudir); if (!CPU_ISSET(core, &core_mask)) {
return -1; CPU_SET(core, &core_mask);
nodeinfo->cores++;
} }
if (!(socket_mask & (1 << socket))) {
socket_mask |= (1 << socket); /* Parse socket */
socket = parse_socket(cpu);
if (!CPU_ISSET(socket, &socket_mask)) {
CPU_SET(socket, &socket_mask);
nodeinfo->sockets++; nodeinfo->sockets++;
} }
@ -360,14 +326,19 @@ int linuxNodeInfoCPUPopulate(FILE *cpuinfo,
} }
if (errno) { if (errno) {
virReportSystemError(errno, virReportSystemError(errno,
_("problem reading %s"), CPU_SYS_PATH); _("problem reading %s"), sysfs_path);
closedir(cpudir); closedir(cpudir);
return -1; return -1;
} }
closedir(cpudir); closedir(cpudir);
/* there should always be at least one socket and one thread */ /* there should always be at least one cpu, socket and one thread */
if (nodeinfo->cpus == 0) {
nodeReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("no CPUs found"));
return -1;
}
if (nodeinfo->sockets == 0) { if (nodeinfo->sockets == 0) {
nodeReportError(VIR_ERR_INTERNAL_ERROR, nodeReportError(VIR_ERR_INTERNAL_ERROR,
"%s", _("no sockets found")); "%s", _("no sockets found"));
@ -611,13 +582,20 @@ int nodeGetInfo(virConnectPtr conn ATTRIBUTE_UNUSED, virNodeInfoPtr nodeinfo) {
#ifdef __linux__ #ifdef __linux__
{ {
int ret; int ret;
char *sysfs_cpuinfo;
FILE *cpuinfo = fopen(CPUINFO_PATH, "r"); FILE *cpuinfo = fopen(CPUINFO_PATH, "r");
if (!cpuinfo) { if (!cpuinfo) {
virReportSystemError(errno, virReportSystemError(errno,
_("cannot open %s"), CPUINFO_PATH); _("cannot open %s"), CPUINFO_PATH);
return -1; return -1;
} }
ret = linuxNodeInfoCPUPopulate(cpuinfo, nodeinfo, true);
if (virAsprintf(&sysfs_cpuinfo, CPU_SYS_PATH) < 0) {
virReportOOMError();
return -1;
}
ret = linuxNodeInfoCPUPopulate(cpuinfo, sysfs_cpuinfo, nodeinfo);
VIR_FORCE_FCLOSE(cpuinfo); VIR_FORCE_FCLOSE(cpuinfo);
if (ret < 0) if (ret < 0)
return -1; return -1;