[libvirt] [PATCH v3] virsh nodecpustats returns incorrect stats of cpu on Linux when the number of online cpu exceed 9.

From: Bing Bu Cao <mars@linux.vnet.ibm.com> To retrieve node cpu statistics on Linux system, the linuxNodeGetCPUstats function simply uses STRPREFIX() to match the cpuid with the cpuid read from /proc/stat, it will cause obvious error. For example: 'virsh nodecpustats 1' will display stats of cpu1* if the latter is online and cpu1 is offline. This patch fixes this bug. Signed-off-by: Bing Bu Cao <mars@linux.vnet.ibm.com> --- src/nodeinfo.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/nodeinfo.c b/src/nodeinfo.c index 05bc038..cf6d29b 100644 --- a/src/nodeinfo.c +++ b/src/nodeinfo.c @@ -691,7 +691,7 @@ linuxNodeGetCPUStats(FILE *procstat, char line[1024]; 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[4 + INT_BUFSIZE_BOUND(cpuNum)]; if ((*nparams) == 0) { /* Current number of cpu stats supported by linux */ @@ -708,9 +708,9 @@ linuxNodeGetCPUStats(FILE *procstat, } if (cpuNum == VIR_NODE_CPU_STATS_ALL_CPUS) { - strcpy(cpu_header, "cpu"); + strcpy(cpu_header, "cpu "); } else { - snprintf(cpu_header, sizeof(cpu_header), "cpu%d", cpuNum); + snprintf(cpu_header, sizeof(cpu_header), "cpu%d ", cpuNum); } while (fgets(line, sizeof(line), procstat) != NULL) { -- 1.7.7.6

On 01/21/2014 06:21 AM, mars@linux.vnet.ibm.com wrote:
From: Bing Bu Cao <mars@linux.vnet.ibm.com>
To retrieve node cpu statistics on Linux system, the linuxNodeGetCPUstats function simply uses STRPREFIX() to match the cpuid with the cpuid read from /proc/stat, it will cause obvious error.
For example: 'virsh nodecpustats 1' will display stats of cpu1* if the latter is online and cpu1 is offline.
This patch fixes this bug.
Signed-off-by: Bing Bu Cao <mars@linux.vnet.ibm.com> --- src/nodeinfo.c | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/src/nodeinfo.c b/src/nodeinfo.c index 05bc038..cf6d29b 100644 --- a/src/nodeinfo.c +++ b/src/nodeinfo.c @@ -691,7 +691,7 @@ linuxNodeGetCPUStats(FILE *procstat, char line[1024]; 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[4 + INT_BUFSIZE_BOUND(cpuNum)];
if ((*nparams) == 0) { /* Current number of cpu stats supported by linux */
I have pushed this hunk, Michal pushed the rest from version 2 of the patch. Could you please take a look at the test I've posted here: https://www.redhat.com/archives/libvir-list/2014-January/msg01022.html and extend it with the /proc/stat file from the machine where you saw the failure? Jan
participants (2)
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Ján Tomko
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mars@linux.vnet.ibm.com