Hi Wei,
Thanks for the review.
On 09/01/2015 01:52 AM, Wei Huang wrote:
On 08/30/2015 10:42 PM, Hemant Kumar wrote:
Running kvm_stat on a powerpc macine where the kernel is compiled with
KVM_BOOK3S_HV_EXIT_TIMING config option, generates the following error :
# kvm_stat
Traceback (most recent call last):
File "/usr/bin/kvm_stat", line 644, in <module>
curses.wrapper(tui, stats)
File "/usr/lib64/python2.7/curses/wrapper.py", line 43, in wrapper
return func(stdscr, *args, **kwds)
File "/usr/bin/kvm_stat", line 550, in tui
refresh(sleeptime)
File "/usr/bin/kvm_stat", line 526, in refresh
s = stats.get()
File "/usr/bin/kvm_stat", line 486, in get
new = d.read()
File "/usr/bin/kvm_stat", line 29, in read
return dict([(key, val(key)) for key in self._fields])
File "/usr/bin/kvm_stat", line 28, in val
return int(file(self.base + '/' + key).read())
IOError: [Errno 21] Is a directory: '/sys/kernel/debug/kvm/vm12840'
The error says that its trying to read the contents of a directory as if
it were a file. The kernel here creates directories inside
"/sys/kernel/debug/kvm/" for the individual VMs running on the
machine. These directories contain timing information (for rm_entry,
rm_intr, rm_exit, guest, cede) related to each vcpu of each VM. All of
this is enabled with KVM_BOOK3S_HV_EXIT_TIMING config option for the
kernel.
A suggestion: would it be useful to display these statistics in
perf_stat? I understand that these counters are per-vm-based; but they
might provide useful insights to end-users.
It would be definitely useful to display these statistics, but since this
script doesn't work on powerpc with the config option enabled, this
patch should work as a fix for now.
We can work on enhancing kvm_stat to display these per vm statistics.
kvm_stat script isn't supposed to parse/read these directories and isn't
even expecting any directories inside "/sys/kernel/debug/kvm/". This
patch fixes the problem by avoiding lookup for these directories.
Reported-by: Krishnaja Balachandran <kriba...@in.ibm.com>
Signed-off-by: Hemant Kumar <hem...@linux.vnet.ibm.com>
---
scripts/kvm/kvm_stat | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/scripts/kvm/kvm_stat b/scripts/kvm/kvm_stat
index 7e5d256..1da7a53 100755
--- a/scripts/kvm/kvm_stat
+++ b/scripts/kvm/kvm_stat
@@ -18,7 +18,11 @@ from ctypes import *
class DebugfsProvider(object):
def __init__(self):
self.base = '/sys/kernel/debug/kvm'
- self._fields = os.listdir(self.base)
+ files = os.listdir(self.base)
+ self._fields = []
+ for f in files:
+ if os.path.isfile(self.base + '/' + f):
+ self._fields.append(f)
def fields(self):
return self._fields
def select(self, fields):
I tested this patch on x86 box and didn't see any problem. So:
Reviewed-by: Wei Huang <w...@redhat.com>
Thanks!
--
Hemant Kumar