Get thread and socket information in virsh nodeinfo.

The current code for "nodeinfo" is pretty naive
about socket and thread information.  To determine the
sockets, it just takes the number of cpus and divides
by the number of cores.  For the thread count, it always
sets it to 1.  With more recent Intel machines, however,
hyperthreading is again an option, meaning that these
heuristics no longer work and give bogus numbers.  This
patch goes through /sys to get the additional
information so we properly report it.

Note that I had to edit the tests not to report on
socket and thread counts, since these are determined
dynamically now.

v2: As pointed out by Eric Blake, gnulib provides
    count-one-bits (which is LGPLv2+).  Use it instead
    of a hand-coded popcnt.
Signed-off-by: NChris Lalancette <clalance@redhat.com>

bootstrap.conf

@@ -25,6 +25,7 @@ c-ctype
 canonicalize-lgpl
 close
 connect
+count-one-bits
 dirname-lgpl
 getaddrinfo
 gethostname

src/nodeinfo.c

@@ -28,6 +28,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <errno.h>
+#include <dirent.h>
 
 #if HAVE_NUMACTL
 # define NUMA_VERSION1_COMPATIBILITY 1
@@ -45,6 +46,7 @@
 #include "util.h"
 #include "logging.h"
 #include "virterror_internal.h"
+#include "count-one-bits.h"
 
 
 #define VIR_FROM_THIS VIR_FROM_NONE
@@ -55,22 +57,109 @@
 
 #ifdef __linux__
 #define CPUINFO_PATH "/proc/cpuinfo"
+#define CPU_SYS_PATH "/sys/devices/system/cpu"
 
-/* NB, these are not static as we need to call them from testsuite */
+/* NB, this is not static as we need to call it from the testsuite */
 int linuxNodeInfoCPUPopulate(virConnectPtr conn, FILE *cpuinfo,
                              virNodeInfoPtr nodeinfo);
 
-int linuxNodeInfoCPUPopulate(virConnectPtr conn, FILE *cpuinfo, virNodeInfoPtr nodeinfo) {
+static unsigned long count_thread_siblings(int cpu)
+{
+    unsigned long ret = 0;
+    char *path = NULL;
+    FILE *pathfp = NULL;
+    char str[1024];
+    int i;
+
+    if (virAsprintf(&path, "%s/cpu%d/topology/thread_siblings", CPU_SYS_PATH,
+                    cpu) < 0) {
+        virReportOOMError();
+        return 0;
+    }
+
+    pathfp = fopen(path, "r");
+    if (pathfp == NULL) {
+        virReportSystemError(errno, _("cannot open %s"), path);
+        VIR_FREE(path);
+        return 0;
+    }
+
+    if (fgets(str, sizeof(str), pathfp) == NULL) {
+        virReportSystemError(errno, _("cannot read from %s"), path);
+        goto cleanup;
+    }
+
+    i = 0;
+    while (str[i] != '\0') {
+        if (str[i] != '\n' && str[i] != ',')
+            ret += count_one_bits(str[i] - '0');
+        i++;
+    }
+
+cleanup:
+    fclose(pathfp);
+    VIR_FREE(path);
+
+    return ret;
+}
+
+static int parse_socket(int cpu)
+{
+    char *path = NULL;
+    FILE *pathfp;
+    char socket_str[1024];
+    char *tmp;
+    int socket;
+
+    if (virAsprintf(&path, "%s/cpu%d/topology/physical_package_id",
+                    CPU_SYS_PATH, cpu) < 0) {
+        virReportOOMError();
+        return -1;
+    }
+
+    pathfp = fopen(path, "r");
+    if (pathfp == NULL) {
+        virReportSystemError(errno, _("cannot open %s"), path);
+        goto cleanup;
+    }
+
+    if (fgets(socket_str, sizeof(socket_str), pathfp) == NULL) {
+        virReportSystemError(errno, _("cannot read from %s"), path);
+        goto cleanup;
+    }
+    if (virStrToLong_i(socket_str, &tmp, 10, &socket) < 0) {
+        nodeReportError(NULL, VIR_ERR_INTERNAL_ERROR,
+                        _("could not convert '%s' to an integer"),
+                        socket_str);
+        goto cleanup;
+    }
+
+cleanup:
+    fclose(pathfp);
+    VIR_FREE(path);
+
+    return socket;
+}
+
+int linuxNodeInfoCPUPopulate(virConnectPtr conn, FILE *cpuinfo,
+                             virNodeInfoPtr nodeinfo)
+{
     char line[1024];
+    DIR *cpudir = NULL;
+    struct dirent *cpudirent = NULL;
+    int cpu;
+    unsigned long cur_threads;
+    int socket;
+    unsigned long long socket_mask = 0;
 
     nodeinfo->cpus = 0;
     nodeinfo->mhz = 0;
-    nodeinfo->nodes = nodeinfo->sockets = nodeinfo->cores = nodeinfo->threads = 1;
+    nodeinfo->nodes = nodeinfo->cores = 1;
 
     /* NB: It is impossible to fill our nodes, since cpuinfo
      * has not knowledge of NUMA nodes */
 
-    /* XXX hyperthreads */
+    /* NOTE: hyperthreads are ignored here; they are parsed out of /sys */
     while (fgets(line, sizeof(line), cpuinfo) != NULL) {
         char *buf = line;
         if (STRPREFIX(buf, "processor")) { /* aka a single logical CPU */
@@ -122,12 +211,38 @@ int linuxNodeInfoCPUPopulate(virConnectPtr conn, FILE *cpuinfo, virNodeInfoPtr n
         return -1;
     }
 
-    /*
-     * Can't reliably count sockets from proc metadata, so
-     * infer it based on total CPUs vs cores.
-     * XXX hyperthreads
+    /* OK, we've parsed what we can out of /proc/cpuinfo.  Get the socket
+     * and thread information from /sys
      */
-    nodeinfo->sockets = nodeinfo->cpus / nodeinfo->cores;
+    cpudir = opendir(CPU_SYS_PATH);
+    if (cpudir == NULL) {
+        virReportSystemError(errno, _("cannot opendir %s"), CPU_SYS_PATH);
+        return -1;
+    }
+    while ((cpudirent = readdir(cpudir))) {
+        if (sscanf(cpudirent->d_name, "cpu%d", &cpu) != 1)
+            continue;
+
+        socket = parse_socket(cpu);
+        if (socket < 0) {
+            closedir(cpudir);
+            return -1;
+        }
+        if (!(socket_mask & (1 << socket))) {
+            socket_mask |= (1 << socket);
+            nodeinfo->sockets++;
+        }
+
+        cur_threads = count_thread_siblings(cpu);
+        if (cur_threads == 0) {
+            closedir(cpudir);
+            return -1;
+        }
+        if (cur_threads > nodeinfo->threads)
+            nodeinfo->threads = cur_threads;
+    }
+
+    closedir(cpudir);
 
     return 0;
 }

tests/nodeinfodata/linux-nodeinfo-1.txt

-CPUs: 2, MHz: 2800, Nodes: 1, Sockets: 1, Cores: 2, Threads: 1
+CPUs: 2, MHz: 2800, Nodes: 1, Cores: 2

tests/nodeinfodata/linux-nodeinfo-2.txt

-CPUs: 2, MHz: 2211, Nodes: 1, Sockets: 1, Cores: 2, Threads: 1
+CPUs: 2, MHz: 2211, Nodes: 1, Cores: 2

tests/nodeinfodata/linux-nodeinfo-3.txt

-CPUs: 4, MHz: 1595, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 1595, Nodes: 1, Cores: 2

tests/nodeinfodata/linux-nodeinfo-4.txt

-CPUs: 4, MHz: 1000, Nodes: 1, Sockets: 1, Cores: 4, Threads: 1
+CPUs: 4, MHz: 1000, Nodes: 1, Cores: 4

tests/nodeinfodata/linux-nodeinfo-5.txt

-CPUs: 4, MHz: 2814, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 2814, Nodes: 1, Cores: 2

tests/nodeinfodata/linux-nodeinfo-6.txt

-CPUs: 4, MHz: 1000, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 1000, Nodes: 1, Cores: 2

tests/nodeinfotest.c

@@ -47,9 +47,8 @@ static int linuxTestCompareFiles(const char *cpuinfofile, const char *outputfile
     fclose(cpuinfo);
 
     snprintf(actualData, MAX_FILE,
-             "CPUs: %u, MHz: %u, Nodes: %u, Sockets: %u, Cores: %u, Threads: %u\n",
-             nodeinfo.cpus, nodeinfo.mhz, nodeinfo.nodes, nodeinfo.sockets,
-             nodeinfo.cores, nodeinfo.threads);
+             "CPUs: %u, MHz: %u, Nodes: %u, Cores: %u\n",
+             nodeinfo.cpus, nodeinfo.mhz, nodeinfo.nodes, nodeinfo.cores);
 
     if (STRNEQ(actualData, expectData)) {
         if (getenv("DEBUG_TESTS")) {