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[libvirt] [PATCH] 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: Chris Lalancette <clalance redhat com>
---
 bootstrap.conf                          |    1 +
 src/nodeinfo.c                          |  133 ++++++++++++++++++++++++++++--
 tests/nodeinfodata/linux-nodeinfo-1.txt |    2 +-
 tests/nodeinfodata/linux-nodeinfo-2.txt |    2 +-
 tests/nodeinfodata/linux-nodeinfo-3.txt |    2 +-
 tests/nodeinfodata/linux-nodeinfo-4.txt |    2 +-
 tests/nodeinfodata/linux-nodeinfo-5.txt |    2 +-
 tests/nodeinfodata/linux-nodeinfo-6.txt |    2 +-
 tests/nodeinfotest.c                    |    5 +-
 9 files changed, 133 insertions(+), 18 deletions(-)

diff --git a/bootstrap.conf b/bootstrap.conf
index 58ef2ab..157092f 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -25,6 +25,7 @@ c-ctype
 canonicalize-lgpl
 close
 connect
+count-one-bits
 dirname-lgpl
 getaddrinfo
 gethostname
diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index 2d44609..b645e0e 100644
--- a/src/nodeinfo.c
+++ b/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;
 }
diff --git a/tests/nodeinfodata/linux-nodeinfo-1.txt b/tests/nodeinfodata/linux-nodeinfo-1.txt
index e52e20a..09e2946 100644
--- a/tests/nodeinfodata/linux-nodeinfo-1.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-1.txt
@@ -1 +1 @@
-CPUs: 2, MHz: 2800, Nodes: 1, Sockets: 1, Cores: 2, Threads: 1
+CPUs: 2, MHz: 2800, Nodes: 1, Cores: 2
diff --git a/tests/nodeinfodata/linux-nodeinfo-2.txt b/tests/nodeinfodata/linux-nodeinfo-2.txt
index 12e819b..e4eea94 100644
--- a/tests/nodeinfodata/linux-nodeinfo-2.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-2.txt
@@ -1 +1 @@
-CPUs: 2, MHz: 2211, Nodes: 1, Sockets: 1, Cores: 2, Threads: 1
+CPUs: 2, MHz: 2211, Nodes: 1, Cores: 2
diff --git a/tests/nodeinfodata/linux-nodeinfo-3.txt b/tests/nodeinfodata/linux-nodeinfo-3.txt
index d285781..17d4d8e 100644
--- a/tests/nodeinfodata/linux-nodeinfo-3.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-3.txt
@@ -1 +1 @@
-CPUs: 4, MHz: 1595, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 1595, Nodes: 1, Cores: 2
diff --git a/tests/nodeinfodata/linux-nodeinfo-4.txt b/tests/nodeinfodata/linux-nodeinfo-4.txt
index 991d4f9..5a5c919 100644
--- a/tests/nodeinfodata/linux-nodeinfo-4.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-4.txt
@@ -1 +1 @@
-CPUs: 4, MHz: 1000, Nodes: 1, Sockets: 1, Cores: 4, Threads: 1
+CPUs: 4, MHz: 1000, Nodes: 1, Cores: 4
diff --git a/tests/nodeinfodata/linux-nodeinfo-5.txt b/tests/nodeinfodata/linux-nodeinfo-5.txt
index dce7ada..54abb5d 100644
--- a/tests/nodeinfodata/linux-nodeinfo-5.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-5.txt
@@ -1 +1 @@
-CPUs: 4, MHz: 2814, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 2814, Nodes: 1, Cores: 2
diff --git a/tests/nodeinfodata/linux-nodeinfo-6.txt b/tests/nodeinfodata/linux-nodeinfo-6.txt
index 75cdaa9..f89e35e 100644
--- a/tests/nodeinfodata/linux-nodeinfo-6.txt
+++ b/tests/nodeinfodata/linux-nodeinfo-6.txt
@@ -1 +1 @@
-CPUs: 4, MHz: 1000, Nodes: 1, Sockets: 2, Cores: 2, Threads: 1
+CPUs: 4, MHz: 1000, Nodes: 1, Cores: 2
diff --git a/tests/nodeinfotest.c b/tests/nodeinfotest.c
index 4cb248a..b3b91ad 100644
--- a/tests/nodeinfotest.c
+++ b/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")) {
-- 
1.6.6.1


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