On Wed, 2005-03-02 at 14:04 +0900, FUJITA Tomonori wrote: > From: FUJITA Tomonori <[EMAIL PROTECTED]> > Subject: [Iscsitarget-devel] Re: [ANNOUNCE] iSCSI enterprise target software > Date: Tue, 01 Mar 2005 18:35:49 +0900 > > > The last reason is that user-space cost like memory copy. With 1Gbs > > Ethernet, is is not critical. However, with 10G, it is critical, I > > expect. I've been setting up 10G experimental infrastructure to > > evaluate iSCSI performance. > > If we try to build high-performance iSCSI target software on 10Gbs > Ethernet, I think that we need to implement it in the kernel > space, although this topic is still in the research stage. > > IICR, Intel provides open-source iSCSI target software, which uses > mmap() in the user space, as you suggested. However, they chose a > different approach to implement iSCSI target software for 10Gbs. They > modified the Linux kernel TCP stack to fully integrate iSCSI > functionality with it. It is still not clear how to get the best > performance out of 10GBs Ethernet, however, it seems that using just > the socket interface is not good enough. So I think that we need to > control all the system-resources to do it. > > We've not optimized our code yet. The current code simply uses the > socket interface, however, moving some functionality to the TCP stack > can improve the performance, although I don't plan to modify theu TCP > stack. A possible approach to do it is exploiting sk_data_ready().
www.open-iscsi.org project uses this technique on receiving path and shows very nice performance numbers for Read operations comparable with HW accelerators. To add such a functionality to an existing project will probably require total re-design. Regards, Dima - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
