Re: [Qemu-devel] [PATCH v5 5/5] qemu-iotests: Add 093 for IO throttling

[Fam Zheng <famz@redhat.com>]

On Tue, 01/27 11:14, Max Reitz wrote:
> On 2015-01-26 at 22:03, Fam Zheng wrote:
> >On Mon, 01/26 15:45, Max Reitz wrote:
> >>On 2015-01-16 at 03:46, Fam Zheng wrote:
> >>>This case utilizes qemu-io command "aio_{read,write} -q" to verify the
> >>>effectiveness of IO throttling options.
> >>>
> >>>It's implemented by driving the vm timer from qtest protocol, so the
> >>>throttling timers are signaled with determinied time duration. Then we
> >>>verify the completed IO requests are within 10% error of bps and iops
> >>>limits.
> >>>
> >>>"null" protocol is used as the disk backend so that no actual disk IO is
> >>>performed on host, this will make the blockstats much more
> >>>deterministic. Both "null-aio" and "null-co" are covered, which is also
> >>>a simple cross validation test for the driver code.
> >>>
> >>>Signed-off-by: Fam Zheng <famz@redhat.com>
> >>>---
> >>>  tests/qemu-iotests/093     | 103 +++++++++++++++++++++++++++++++++++++++++++++
> >>>  tests/qemu-iotests/093.out |   5 +++
> >>>  tests/qemu-iotests/group   |   1 +
> >>>  3 files changed, 109 insertions(+)
> >>>  create mode 100755 tests/qemu-iotests/093
> >>>  create mode 100644 tests/qemu-iotests/093.out
> >>NACK. This literally kills my laptop (I can recover when running this test
> >>in tmpfs (for some reason inexplicable to me, since this uses the null block
> >>drivers...), but I cannot when running it on my HDD).
> >>
> >>Would it be possible to use larger requests and smaller iops? (Or just the
> >>same request size but smaller bps as well)
> >Is it because of CPU or memory? 1000 requests for both read and write seem to
> >be overkilling since we are measuring 1000 bps and 10 iops, please try if
> >reducing to 100 requests works for you.
> 
> Probably memory, since I seem to recall you having the same model as me, but
> I can imagine you having more RAM...
> 
> 100 requests do not work with 128,000 bps/64 iops/10 seconds (because that'd
> be more than 1 MB of data, whereas 100 requests of 4 kB are of course only
> 400 kB), but the following constellations work:

Oops, I changed bps and iops limits in v5 but was talking about 1000/10 here.
We can still lower the limits though. I'll send a v6 for you to try soon.

Fam