This patch reports the square sum in addition to the classic sum/count
(+min/max) to allow more details statistical post processing.
That way you can process average, % of whole duration and using the
square sum also the standard deviation.
A simple way to get these numbers with awk is:
#!/bin/bash
echo "processing file ${1}"
sumsum=`awk 'BEGIN { csum=0; sumsum=0; count=0}{ csum=csum+$3; count++;
sumsum = sumsum+$9;}END { printf("%s\n", sumsum)}' $1`
echo "sum of time ${sumsum}"
awk '!/count 0/ { printf("%s",$0); printf(" avg %16.4lf stddev
%12.3lf %% %5.2f\n",$9/$3, sqrt($11/$3-(($9/$3)*($9/$3))),
($9/('$sumsum'/100))); }' $1
This runs awk twice, because for % of overall time you need the sum the
durations and I personally don't like all those "rewind hacks" for awk.
Ehrhardt Christian wrote:
From: Christian Ehrhardt <ehrhardt@xxxxxxxxxxxxxxxxxx>
Other existing kvm stats are either just counters (kvm_stat) reported for kvm
generally or trace based aproaches like kvm_trace.
For kvm on powerpc we had the need to track the timings of the different exit
types. While this could be achieved parsing data created with a kvm_trace
extension this adds too muhc overhead (at least on embedded powerpc) slowing
down the workloads we wanted to measure.
Therefore this patch adds a in kernel exit timing statistic to the powerpc kvm
code. These statistic is available per vm&vcpu under the kvm debugfs directory.
As this statistic is low, but still some overhead it can be enabled via a
.config entry and should be off by default.
Since this patch touched all powerpc kvm_stat code anyway this code is now
merged and simpliefied together with the exit timing statistic code (still
working with exit timing disabled in .config).
Here is a sample output (after postprocessing with the awk script I'll post in reply to this patch) how the results look like.
sum of time 27504898
MMIO: count 824 min 51 max 555 sum 75825 sum_quad 9232871 avg 92.0206 stddev 52.318 % 0.28
DCR: count 140 min 44 max 92 sum 6746 sum_quad 327658 avg 48.1857 stddev 4.307 % 0.02
SIGNAL: count 2 min 309 max 993 sum 1302 sum_quad 1081530 avg 651.0000 stddev 342.000 % 0.00
ITLBREAL: count 293 min 11 max 14 sum 3515 sum_quad 42175 avg 11.9966 stddev 0.155 % 0.01
ITLBVIRT: count 113822 min 20 max 338 sum 2595412 sum_quad 60256824 avg 22.8024 stddev 3.074 % 9.44
DTLBREAL: count 242 min 11 max 14 sum 2908 sum_quad 34974 avg 12.0165 stddev 0.352 % 0.01
DTLBVIRT: count 66687 min 21 max 329 sum 1530048 sum_quad 35434926 avg 22.9437 stddev 2.224 % 5.56
SYSCALL: count 72 min 9 max 10 sum 649 sum_quad 5851 avg 9.0139 stddev 0.117 % 0.00
ISI: count 56 min 9 max 10 sum 506 sum_quad 4574 avg 9.0357 stddev 0.186 % 0.00
DSI: count 49 min 9 max 10 sum 448 sum_quad 4102 avg 9.1429 stddev 0.350 % 0.00
EMULINST: count 211220 min 7 max 7700 sum 3292984 sum_quad 5797023806 avg 15.5903 stddev 164.931 % 11.97
DEC: count 6582 min 49 max 322 sum 367567 sum_quad 22996737 avg 55.8443 stddev 19.373 % 1.34
EXTINT: count 4 min 79 max 513 sum 797 sum_quad 290423 avg 199.2500 stddev 181.398 % 0.00
TIMEINGUEST: count 399993 min 0 max 3952 sum 19626191 sum_quad 61148587807 avg 49.0663 stddev 387.900 % 71.36
Signed-off-by: Christian Ehrhardt <ehrhardt@xxxxxxxxxxxxxxxxxx>
---
[diffstat]
arch/powerpc/include/asm/kvm_host.h | 49 ++++++++
arch/powerpc/include/asm/kvm_timing_stats.h | 142 ++++++++++++++++++++++++
arch/powerpc/include/asm/mmu-44x.h | 1
arch/powerpc/kernel/asm-offsets.c | 11 +
arch/powerpc/kvm/Kconfig | 9 +
arch/powerpc/kvm/booke.c | 35 +++---
arch/powerpc/kvm/booke.h | 7 +
arch/powerpc/kvm/booke_interrupts.S | 24 ++++
arch/powerpc/kvm/powerpc.c | 163 +++++++++++++++++++++++++++-
9 files changed, 425 insertions(+), 16 deletions(-)
[diff]
[...]
--
Grüsse / regards,
Christian Ehrhardt
IBM Linux Technology Center, Open Virtualization
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