Re: [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention

2014-08-20 Thread Bart Van Assche
On 08/19/14 20:17, kashyap.de...@avagotech.com wrote: + if (shost-hostt-enable_cmd_list) { This code is in the hot path which means that caching enable_cmd_list in struct Scsi_Host (as is done for many other SCSI host parameters) probably will (slightly) improve performance further.

RE: [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention

2014-08-20 Thread Kashyap Desai
] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention On 08/19/14 20:17, kashyap.de...@avagotech.com wrote: + if (shost-hostt-enable_cmd_list) { This code is in the hot path which means that caching enable_cmd_list in struct Scsi_Host (as is done for many other SCSI host

RE: [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention

2014-08-20 Thread Kashyap Desai
] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention On Wed, Aug 20, 2014 at 06:08:37PM +0530, Kashyap Desai wrote: This code is in the hot path which means that caching enable_cmd_list in struct Scsi_Host (as is done for many other SCSI host parameters) probably

Re: [PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention

2014-08-20 Thread Christoph Hellwig
On Wed, Aug 20, 2014 at 06:08:37PM +0530, Kashyap Desai wrote: This code is in the hot path which means that caching enable_cmd_list in struct Scsi_Host (as is done for many other SCSI host parameters) probably will (slightly) improve performance further. Otherwise this patch looks fine

[PATCH] scsi.mq:Added enable_cmd_list flags in hostt to reduce lock contention

2014-08-19 Thread Kashyap.Desai
Add enable_cmd_list flag in shost template to indicate scs.mq stack to keep track of cmd_list per sdev. Default behaviour is not to keep track of cmd_list per sdev, as this may introduce lock contention. (overhead is more on multi-node NUMA.) Patch is tested using megaraid_sas driver with