On Fri, May 2, 2008 at 6:18 PM, James Bottomley <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> wrote: > On Fri, 2008-05-02 at 18:06 +0200, Bart Van Assche wrote: >> Regarding inclusion of SCSI target code in the mainline, this subject >> has already been discussed extensively in the past >> (http://lkml.org/lkml/2008/1/23/134). The conclusion was clear: SCST >> is faster than any other existing iSCSI target for Linux (IET, STGT, >> LIO), stable, well maintained and the most standards compliant target. >> Why do you want to reopen this discussion ? > > That's an interesting rewrite of history. The evidence you presented > showed fairly identical results apart from on one contrived IB benchmark > that couldn't directly compare the two. > > I'm also on record in the thread saying that was insufficient proof for > me to justify throwing STGT out and replacing it with SCST. The trend of the measurements I did was very clear: SCST has a higher bandwidth and a lower latency than the other three iSCSI implementations I benchmarked. While this difference is neglectible for 100 Mbit/s media, the difference is significant for 10 Gbit/s media. One of the tests I did was with iSCSI via IPoIB. These results allow direct comparison between STGT and SCST. >> James Bottomley clearly expressed in that thread that he doesn't want >> to maintain two SCSI target frameworks. So what I propose is that SCST >> is included in the mainline and afterwards that it is evaluated >> whether or not it is desirable to keep other target code in the >> mainline kernel. > > That's hardly sufficient. STGT is already in use. Their either has to > be a migration path or, the preferred option, take the pieces of SCST > that are actual improvements and embed them in STGT. In the thread I referred to it has been explained that for optimal speed and minimum latency a kernelspace implementation is required. Since most of STGT is implemented in userspace, embedding pieces of SCST in STGT is not an option. Bart. -- 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
