Hi all,
I'd like to discuss the current state of scsi-mq prototype code.
And now that blk-mq is upstream for v3.13, exploring the remaining TODO
items towards an initial scsi-mq merge sometime before 2015 is upon us.
The benefits of scsi-mq remain unchanged:
- Utilizes blk-mq's native per-cpu primitive + NUMA local friendly
queuing of pre-allocated struct request descriptor memory
- Eliminates all fast-path memory allocations in SCSI-core +
optionally the underlying SCSI LLDs
- Avoids fast-path Scsi_Host->host_lock + request_queue->queue_lock
accesses in submission + completion paths
These benefits have been discussed in greater detail in [1], and the
latest alpha quality code is available at [2] below.
The current TODO items include:
- A plan for per device SCSI error handling
- Proper scsi_device->sdev_gendev reference counting
- Queuing fairness across multiple scsi-mq devices per host
- Support for > 1 nr_hw_queues + conversion of qla2xxx + lpfc
LLDs that support native hardware multiqueue
Thank you,
--nab
References:
[1]:
[ATTEND] scsi-mq prototype discussion
http://marc.info/?l=linux-scsi&m=137358831329753&w=2
[2]:
scsi-mq WIP updated to v3.13-rc3
http://marc.info/?l=linux-scsi&m=138782535731722&w=2
On 1/16/2014 1:05 AM, Nicholas A. Bellinger wrote:
> Hi all,
>
> I'd like to discuss the current state of scsi-mq prototype code.
>
> And now that blk-mq is upstream for v3.13, exploring the remaining TODO
> items towards an initial scsi-mq merge sometime before 2015 is upon us.
>
> The benefits of scsi-mq remain unchanged:
>
> - Utilizes blk-mq's native per-cpu primitive + NUMA local friendly
> queuing of pre-allocated struct request descriptor memory
> - Eliminates all fast-path memory allocations in SCSI-core +
> optionally the underlying SCSI LLDs
> - Avoids fast-path Scsi_Host->host_lock + request_queue->queue_lock
> accesses in submission + completion paths
>
> These benefits have been discussed in greater detail in [1], and the
> latest alpha quality code is available at [2] below.
>
> The current TODO items include:
>
> - A plan for per device SCSI error handling
> - Proper scsi_device->sdev_gendev reference counting
> - Queuing fairness across multiple scsi-mq devices per host
> - Support for > 1 nr_hw_queues + conversion of qla2xxx + lpfc
> LLDs that support native hardware multiqueue
>
> Thank you,
>
> --nab
>
> References:
>
> [1]:
> [ATTEND] scsi-mq prototype discussion
> http://marc.info/?l=linux-scsi&m=137358831329753&w=2
>
> [2]:
> scsi-mq WIP updated to v3.13-rc3
> http://marc.info/?l=linux-scsi&m=138782535731722&w=2
>
+1
I would be happy to join this discussion, I think it is also important
to think about the interaction with iSCSI and LLDs.
Sagi.
James,
I'd like to attend to participate in the EH, MQ, and T10 PI RDMA
discussions.
-- james s
On 1/16/2014 11:29 AM, Sagi Grimberg wrote:
> On 1/16/2014 1:05 AM, Nicholas A. Bellinger wrote:
>> Hi all,
>>
>> I'd like to discuss the current state of scsi-mq prototype code.
>>
>> And now that blk-mq is upstream for v3.13, exploring the remaining TODO
>> items towards an initial scsi-mq merge sometime before 2015 is upon us.
>>
>> The benefits of scsi-mq remain unchanged:
>>
>> - Utilizes blk-mq's native per-cpu primitive + NUMA local friendly
>> queuing of pre-allocated struct request descriptor memory
>> - Eliminates all fast-path memory allocations in SCSI-core +
>> optionally the underlying SCSI LLDs
>> - Avoids fast-path Scsi_Host->host_lock + request_queue->queue_lock
>> accesses in submission + completion paths
>>
>> These benefits have been discussed in greater detail in [1], and the
>> latest alpha quality code is available at [2] below.
>>
>> The current TODO items include:
>>
>> - A plan for per device SCSI error handling
>> - Proper scsi_device->sdev_gendev reference counting
>> - Queuing fairness across multiple scsi-mq devices per host
>> - Support for > 1 nr_hw_queues + conversion of qla2xxx + lpfc
>> LLDs that support native hardware multiqueue
>>
>> Thank you,
>>
>> --nab
>>
>> References:
>>
>> [1]:
>> [ATTEND] scsi-mq prototype discussion
>> http://marc.info/?l=linux-scsi&m=137358831329753&w=2
>>
>> [2]:
>> scsi-mq WIP updated to v3.13-rc3
>> http://marc.info/?l=linux-scsi&m=138782535731722&w=2
>>
>
> +1
> I would be happy to join this discussion, I think it is also important
> to think about the interaction with iSCSI and LLDs.
>
> Sagi.
>
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