Ok. Reading Mike's comment once again and looking at the lpfc code ,I think, maybe, this is what Mike had in mind, but I could have misunderstood. During session create, I will create the pool as well as alloc. This will take care of the allocation at page level and scarce coherent resources problems mentioned by JamesB. Also, this would not have any impact on performance. I see this done for "lpfc_mbuf_pool" in lpfc/lpfc_mem.c. Thanks Jay _____ From: James Bottomley [mailto:James.Bottomley@xxxxxxx] To: Jayamohan Kalickal [mailto:jayamohank@xxxxxxxxxxxxxxxxx] Cc: Mike Christie [mailto:michaelc@xxxxxxxxxxx], linux-scsi@xxxxxxxxxxxxxxx, sfr@xxxxxxxxxxxxxxxx Sent: Thu, 10 Sep 2009 10:15:40 -0700 Subject: Re: [PATCH 1/1] be2iscsi: Fixes for powerpc compile On Wed, 2009-09-09 at 12:15 -0700, Jayamohan Kalickal wrote: > Implementing pci_pool is not a problem. But, my experience with this chip > (or for that matter any chip that can do huge IOPS ,say, more then 600 -700 KIOPS), > every line of code on the hot path would have an impact and hence I strive to > move it out of the hot path. > > The code is not yet optimized for speed yet but I definitely want to push whatever > I can to init time from the IO path. I'll fold in the patch as is because we urgently need a fix for the virt_to_bus() problem. pci_pool was designed to allow for good IOP throughput (that's why lpfc is using it). The pci_alloc_consistent() you've chosen often only allocates at the page level, so it can be hugely wasteful of resources; plus coherent memory is a precious resource on some platforms, so I can see you running out on them. Could you at least try a pci_pool implementation ... if it really turns out to be a performance problem we can keep the current implementation despite the potential resource issues. Thanks, James -- 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 ___________________________________________________________________________________ This message, together with any attachment(s), contains confidential and proprietary information of ServerEngines Corporation and is intended only for the designated recipient(s) named above. Any unauthorized review, printing, retention, copying, disclosure or distribution is strictly prohibited. If you are not the intended recipient of this message, please immediately advise the sender by reply email message and delete all copies of this message and any attachment(s). Thank you. -- 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
