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Re: [libvirt] [PATCH] Get thread and socket information in virsh nodeinfo.



On Fri, Mar 05, 2010 at 02:06:34PM -0500, Chris Lalancette wrote:
> 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")) {

  ACK to this version too, better actually !

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/


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