Re: [PATCH] target/user: Add daynmic growing data area featuresupport

From: Mike Christie
Date: Tue Feb 28 2017 - 13:42:29 EST


On 02/27/2017 07:22 PM, Xiubo Li wrote:
> Hi Mike
>
> Thanks verrry much for your work and test cases.
>
>
>>>>> From: Xiubo Li <lixiubo@xxxxxxxxxxxxxxxxxxxx>
>>>>>
>>>>> Currently for the TCMU, the ring buffer size is fixed to 64K cmd
>>>>> area + 1M data area, and this will be bottlenecks for high iops.
>>> Hi Xiubo, thanks for your work.
>>>
>>> daynmic -> dynamic
>>>
>>> Have you benchmarked this patch and determined what kind of iops
>>> improvement it allows? Do you see the data area reaching its
>>> fully-allocated size?
>>>
>> I tested this patch with Venky's tcmu-runner rbd aio patches, with one
>> 10 gig iscsi session, and for pretty basic fio direct io (64 -256K
>> read/writes with a queue depth of 64 numjobs between 1 and 4) tests read
>> throughput goes from about 80 to 500 MB/s.
> Looks nice.
>
>> Write throughput is pretty
>> low at around 150 MB/s.
> What's the original write throughput without this patch? Is it also
> around 80 MB/s ?

It is around 20-30 MB/s. Same fio args except using --rw=write.