Re: [libvirt] [PATCH] Get thread and socket information in virsh nodeinfo.
On 03/05/2010 12:06 PM, Chris Lalancette wrote:
+#define CPU_SYS_PATH "/sys/devices/system/cpu"
+ if (virAsprintf(&path, "%s/cpu%d/topology/thread_siblings",
CPU_SYS_PATH,
+ cpu) < 0) {
Where is the documentation about what this file will contain? On my
system, I see:
$ cat /sys/devices/system/cpu/cpu0/topology/thread_siblings_list
0
$ cat /sys/devices/system/cpu/cpu0/topology/thread_siblings
00000001
$ cat /sys/devices/system/cpu/cpu1/topology/thread_siblings_list
1
$ cat /sys/devices/system/cpu/cpu1/topology/thread_siblings
00000002
That is, I'm guessing that topology/thread_siblings_list is
human-readable, while topology/thread_siblings is a hex bitmask. If it
is indeed a 32-bit mask, then:
+ 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++;
+ }
...this loop is borked, since it is assuming that str[i] will be a
digit, and is not looking for a-f. And why skipping comma? Shouldn't
this instead be parsing the entire file contents as a single int, and
only then calling count_one_bits once on the result?
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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