On 10/12/2009 05:28 PM, Lucas Meneghel Rodrigues wrote:
Hi Michael, I am reviewing your patchset and have just a minor remark
to make here:
On Wed, Oct 7, 2009 at 2:54 PM, Michael Goldish<mgoldish@xxxxxxxxxx> wrote:
This patch adds a new test that checks the timedrift introduced by migrations.
It uses the same parameters used by the timedrift test to get the guest time.
In addition, the number of migrations the test performs is controlled by the
parameter 'migration_iterations'.
Signed-off-by: Michael Goldish<mgoldish@xxxxxxxxxx>
---
client/tests/kvm/kvm_tests.cfg.sample | 33 ++++---
client/tests/kvm/tests/timedrift_with_migration.py | 95 ++++++++++++++++++++
2 files changed, 115 insertions(+), 13 deletions(-)
create mode 100644 client/tests/kvm/tests/timedrift_with_migration.py
diff --git a/client/tests/kvm/kvm_tests.cfg.sample b/client/tests/kvm/kvm_tests.cfg.sample
index 540d0a2..618c21e 100644
--- a/client/tests/kvm/kvm_tests.cfg.sample
+++ b/client/tests/kvm/kvm_tests.cfg.sample
@@ -100,19 +100,26 @@ variants:
type = linux_s3
- timedrift: install setup
- type = timedrift
extra_params += " -rtc-td-hack"
- # Pin the VM and host load to CPU #0
- cpu_mask = 0x1
- # Set the load and rest durations
- load_duration = 20
- rest_duration = 20
- # Fail if the drift after load is higher than 50%
- drift_threshold = 50
- # Fail if the drift after the rest period is higher than 10%
- drift_threshold_after_rest = 10
- # For now, make sure this test is executed alone
- used_cpus = 100
+ variants:
+ - with_load:
+ type = timedrift
+ # Pin the VM and host load to CPU #0
+ cpu_mask = 0x1
Let's use -smp 2 always.
btw: we need not to parallel the load test with standard tests.
+ # Set the load and rest durations
+ load_duration = 20
+ rest_duration = 20
Even the default duration here seems way too brief here, is there any
reason why 20s was chosen instead of, let's say, 1800s? I am under the
impression that 20s of load won't be enough to cause any noticeable
drift...
+ # Fail if the drift after load is higher than 50%
+ drift_threshold = 50
+ # Fail if the drift after the rest period is higher than 10%
+ drift_threshold_after_rest = 10
I am also curious about those tresholds and the reasoning behind them.
Is there any official agreement on what we consider to be an
unreasonable drift?
Another thing that struck me out is drift calculation: On the original
timedrift test, the guest drift is normalized against the host drift:
drift = 100.0 * (host_delta - guest_delta) / host_delta
While in the new drift tests, we consider only the guest drift. I
believe is better to normalize all tests based on one drift
calculation criteria, and those values should be reviewed, and at
least a certain level of agreement on our development community should
be reached.
I think we don't need to calculate drift ratio. We should define a
threshold in seconds, let's say 2 seconds. Beyond that, there should not
be any drift.
Do we support migration to a different host? We should, especially in
this test too. The destination host reading should also be used.
Apart for that, good patchset, and good thing you refactored some of the
code to shared utils.
Other than this concern that came to my mind, the new tests look good
and work fine here. I had to do a slight rebase in one of the patches,
very minor stuff. The default values and the drift calculation can be
changed on a later time. Thanks!
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
