On 12/19/2013 12:40 PM, Pradipta Kr. Banerjee wrote:
From: "Pradipta Kr. Banerjee" <bpradip@xxxxxxxxxx>
virsh nodecpustats erroneously returns stats for offline cpus on Linux
To retrieve node cpu statistics on Linux system, the
linuxNodeGetCPUstats function performs a minimal match of the input
cpuid with the cpuid read from /proc/cpustat. On systems with larger
cpus this can result in erroneous data.
For eg if /proc/stat has similar data
cpu 3645648 485 361475 3691194868 176595 40645 69850 0 1526172 0
cpu0 494045 62 42763 138516619 16107 2339 2431 0 248345 0
cpu4 402646 59 34745 138617562 17738 1413 1196 0 193948 0
cpu8 318662 32 32119 138715131 7903 927 982 0 115429 0
cpu12 247004 33 30465 138791438 5251 759 913 0 51938 0
and cpu 1,2 are offline, then
'virsh nodecpustats 1' displays data for cpu12
whereas virsh nodecpustats 2 correctly throws the following error
"error: Unable to get node cpu stats
error: Invalid cpuNum in linuxNodeGetCPUStats"
This patch fixes the above mentioned problem
Signed-off-by: Pradipta Kr. Banerjee <bpradip@xxxxxxxxxx>
---
src/nodeinfo.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index 1838547..c9e5ff1 100644
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -614,6 +614,8 @@ linuxNodeGetCPUStats(FILE *procstat,
unsigned long long usr, ni, sys, idle, iowait;
unsigned long long irq, softirq, steal, guest, guest_nice;
char cpu_header[3 + INT_BUFSIZE_BOUND(cpuNum)];
+ char cpu_header_read[3 + INT_BUFSIZE_BOUND(cpuNum)];
+ char cpu_header_fmt[8];
if ((*nparams) == 0) {
/* Current number of cpu stats supported by linux */
@@ -631,8 +633,11 @@ linuxNodeGetCPUStats(FILE *procstat,
if (cpuNum == VIR_NODE_CPU_STATS_ALL_CPUS) {
strcpy(cpu_header, "cpu");
+ snprintf(cpu_header_fmt, sizeof(cpu_header_fmt), "%%%ds", 3);
} else {
snprintf(cpu_header, sizeof(cpu_header), "cpu%d", cpuNum);
+ snprintf(cpu_header_fmt, sizeof(cpu_header_fmt), "%%%ds",
+ (int)(3 + INT_BUFSIZE_BOUND(cpuNum)));
}
while (fgets(line, sizeof(line), procstat) != NULL) {
@@ -649,6 +654,14 @@ linuxNodeGetCPUStats(FILE *procstat,
continue;
}
+ /*
+ * Process with stats gathering only if the cpuid from /proc/stat
+ * matches exactly with the input cpuid
+ */
+ sscanf(buf, cpu_header_fmt, cpu_header_read);
+ if (STRNEQ(cpu_header, cpu_header_read))
+ continue;
+
for (i = 0; i < *nparams; i++) {
virNodeCPUStatsPtr param = ¶ms[i];
What about this?
diff --git a/src/nodeinfo.c b/src/nodeinfo.c
index 1838547..aa1ad81 100644
--- a/src/nodeinfo.c
+++ b/src/nodeinfo.c
@@ -637,8 +637,9 @@ linuxNodeGetCPUStats(FILE *procstat,
while (fgets(line, sizeof(line), procstat) != NULL) {
char *buf = line;
+ char **buf_header = virStringSplit(buf, " ", 2);
- if (STRPREFIX(buf, cpu_header)) { /* aka logical CPU time */
+ if (STREQ(buf_header[0], cpu_header)) { /* aka logical CPU time */
size_t i;
if (sscanf(buf,
@@ -697,6 +698,7 @@ linuxNodeGetCPUStats(FILE *procstat,
ret = 0;
goto cleanup;
}
+ virStringFreeList(buf_header);
}
virReportInvalidArg(cpuNum,
--
1.8.3.1
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