Re: Switching to MQ by default may generate some bug reports

[Ming Lei]

On Tue, Aug 8, 2017 at 7:27 PM, Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote:
> On Tue, Aug 08, 2017 at 06:43:03PM +0800, Ming Lei wrote:
>> Hi Mel Gorman,
>>
>> On Tue, Aug 8, 2017 at 6:30 PM, Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> wrote:
>> ....
>> >
>> > o I've queued a subset of tests with Ming's v3 patchset as that was the
>> >   latest branch at the time I looked. It'll take quite some time to execute
>> >   as the grid I use to collect data is backlogged with other work
>>
>> The latest patchset is in the following post:
>>
>>       http://marc.info/?l=linux-block&m=150191624318513&w=2
>>
>> And you can find it in my github:
>>
>>       https://github.com/ming1/linux/commits/blk-mq-dispatch_for_scsi.V4
>>
>
> Unfortunately, the tests were queued last Friday and are partially complete
> depending on when machines become available. As it is, v3 will take a few
> days to complete and a requeue would incur further delays. If you believe
> the results will be substantially different then I'll discard v3 and requeue.

Firstly V3 on github(never posted out) causes boot hang if CPU cores is >= 16,
so you need to check if the test is still running, :-(

Also V3 on github may not perform well on IB SRP(or other low latency
SCSI disk), so
I improve bio merge in V4 and make IB SRP's perf better too, and it depends on
devices.

I suggest to focus on V2 posted in mail list(V4 in github).

-- 
Ming Lei