On 09/19/2014 06:55 AM, Bart Van Assche wrote: > Hello, > > Although the SRP protocol supports multichannel operation, although > since considerable time RDMA HCA's are available that support multiple > completion vectors and although multichannel operation yields better > performance than using a single channel, the Linux SRP initiator does > not yet support multichannel operation. While adding multichannel > support in the SRP initiator I encountered a few challenges of which I > think these need wider discussion. The topics I would like invite wider > discussion about are as follows: > - How to avoid unneeded inter-socket cache traffic. Should the blk-mq > layer e.g. assign CPU cores to hardware queues such that all CPU cores > associated with a single hardware queue reside on the same CPU socket? > (see also patch 1/8) Right now these are deliberately symmetric, and hence can result in hardware queues being left unused. Whether it makes sense to make this change or not, I think will greatly depend on how many queues are available. There's a crossover point where having more queues doesn't help, and it can even make things worse (interrupt load, etc). For your specific case or 4 queues, it probably DOES make sense to use them all, however. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
