On 12/20/15, 11:13 PM, "target-devel-ow...@vger.kernel.org on behalf of Nicholas A. Bellinger" <target-devel-ow...@vger.kernel.org on behalf of n...@linux-iscsi.org> wrote: >On Thu, 2015-12-17 at 14:57 -0500, Himanshu Madhani wrote: >> From: Quinn Tran <quinn.t...@qlogic.com> >> >> At high traffic, the work queue can become a bottle neck. >> Instead of putting each command on the work queue as 1 work >> element, the fix would daisy chain a list of commands that came >> from FW/interrupt under 1 work element to reduce lock contention. >> > >I'm wondering if we are better served by turning this into generic logic >in kernel/workqueue.c to be used beyond qla2xxx, or: QT> For every work element, the pool->lock is grabbed. Unless the lock can be grab 1 time and the rest of the work elements piggy back on it then it¹s worth it to have a new kernel service. > >using WQ_UNBOUND (following iser-target) and verify if observed >bottleneck is due to internal !(WQ_UNBOUND) usage in qla_target.c. QT> we tried Unbound as one of the low hang fruits. However, Unbound has negative affect when it comes to scaling. > >Out of curiosity, what level of performance improvement does this >patch (as is) actually provide..? QT> By itself ³without" this patch series would be minimal. With the patch series, it allows us to consistently maintain an additional (approx) +50~70k IOPS @4k read. Otherwise, the load is not sustainable or has a chance to increase. The test I use is 2ports Initiator vs 2 ports target, 2 * Qlogic 16G dual port, TCM ramdisk. > >Thank you, > >--nab > >-- >To unsubscribe from this list: send the line "unsubscribe target-devel" in >the body of a message to majord...@vger.kernel.org >More majordomo info at http://vger.kernel.org/majordomo-info.html
<<attachment: winmail.dat>>
