Re: Reg Intel Fortville IXL driver on 11-CURRENT
On Wed, Jun 17, 2015 at 7:00 AM, Lakshmi Narasimhan Sundararajan lakshm...@msystechnologies.com wrote: [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ diff -c5pt ixl_txrx.c ixl_txrx.c.mod *** ixl_txrx.c Fri Jun 12 06:56:51 2015 --- ixl_txrx.c.mod Fri Jun 12 06:56:33 2015 *** ixl_mq_start(struct ifnet *ifp, struct m *** 96,112 --- 96,115 } else #endif i = m-m_pkthdr.flowid % vsi-num_queues; } else i = curcpu % vsi-num_queues; + + #if 0 /* ** This may not be perfect, but until something ** better comes along it will keep from scheduling ** on stalled queues. */ if (((1 i) vsi-active_queues) == 0) i = ffsl(vsi-active_queues); + #endif que = vsi-queues[i]; txr = que-txr; err = drbr_enqueue(ifp, txr-br, m); [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ My understanding is that this code is intended to be triggered as a last resort. If that code is firing regularly then the driver is not correctly tracking which queues are alive in the active_queues bitmask. ___ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to freebsd-net-unsubscr...@freebsd.org
Re: Reg Intel Fortville IXL driver on 11-CURRENT
As Ryan said, its there to keep queues marked as hung from getting more work scheduled on them. I really don't know what to make of it if commenting it out is somehow improving things :) I would suggest more careful analysis of what is going wrong before committing anything like deleting this. Jack On Wed, Jun 17, 2015 at 12:17 PM, Ryan Stone ryst...@gmail.com wrote: On Wed, Jun 17, 2015 at 7:00 AM, Lakshmi Narasimhan Sundararajan lakshm...@msystechnologies.com wrote: [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ diff -c5pt ixl_txrx.c ixl_txrx.c.mod *** ixl_txrx.c Fri Jun 12 06:56:51 2015 --- ixl_txrx.c.mod Fri Jun 12 06:56:33 2015 *** ixl_mq_start(struct ifnet *ifp, struct m *** 96,112 --- 96,115 } else #endif i = m-m_pkthdr.flowid % vsi-num_queues; } else i = curcpu % vsi-num_queues; + + #if 0 /* ** This may not be perfect, but until something ** better comes along it will keep from scheduling ** on stalled queues. */ if (((1 i) vsi-active_queues) == 0) i = ffsl(vsi-active_queues); + #endif que = vsi-queues[i]; txr = que-txr; err = drbr_enqueue(ifp, txr-br, m); [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ My understanding is that this code is intended to be triggered as a last resort. If that code is firing regularly then the driver is not correctly tracking which queues are alive in the active_queues bitmask. ___ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to freebsd-net-unsubscr...@freebsd.org ___ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to freebsd-net-unsubscr...@freebsd.org
Reg Intel Fortville IXL driver on 11-CURRENT
Hi FreeBSD folks, I am part of Panasas and working on evaluating IXL over FreeBSD [11-CURRENT] on Intel Taylor Pass platform for our next product. In that regard, while evaluating performance, we found the Tx performance to be very poor. We found it to be so because the tx interrupts are spread over all the CPUs even if the traffic handling process is pinned at a particular cpu. And we narrowed it down to the below lines of code in the tx path within the IXL driver. It seems to me that the logic for finding whether tx queue is stalled might be incorrect or too aggressive. Either ways, removing the below lines makes the tx interrupt being handled on the same cpu on which the request was raised and the performance is very good as expected. Filename: sys/dev/ixl/ixl_txrx.c [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ diff -c5pt ixl_txrx.c ixl_txrx.c.mod *** ixl_txrx.c Fri Jun 12 06:56:51 2015 --- ixl_txrx.c.mod Fri Jun 12 06:56:33 2015 *** ixl_mq_start(struct ifnet *ifp, struct m *** 96,112 --- 96,115 } else #endif i = m-m_pkthdr.flowid % vsi-num_queues; } else i = curcpu % vsi-num_queues; + + #if 0 /* ** This may not be perfect, but until something ** better comes along it will keep from scheduling ** on stalled queues. */ if (((1 i) vsi-active_queues) == 0) i = ffsl(vsi-active_queues); + #endif que = vsi-queues[i]; txr = que-txr; err = drbr_enqueue(ifp, txr-br, m); [lakshmis@mau-bsd-10a ~/fortville/hol/sys/dev/ixl]$ Would appreciate your feedback on the same. Thanks, LN ___ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to freebsd-net-unsubscr...@freebsd.org
