Date: Thu, 21 Jun 2012 18:30:08 +0530 From: Venkat Duvvuru <venkatduvvuru.ml@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: MSI-X limitation in freebsd 8.2 Message-ID: <CAGdae7ag5YrBTV%2B4-kMmnMOHNcv3h2kbe-_YW=YASATj%2BzspqQ@mail.gmail.com> In-Reply-To: <CAGdae7Yum_MP99kSK1Xi8z02APnZPoXFKR22fTuE5tiuorYMhw@mail.gmail.com> References: <CAGdae7YW0jt4gTmHufHFTrcdtFGhngu_Wi%2BMDg1nY_T0J1C_SQ@mail.gmail.com> <201206201054.40824.jhb@freebsd.org> <CAGdae7anhqdzacVt-BMv3e7GvKFO4QbYEVxd9k-agGjLfPi_iQ@mail.gmail.com> <201206210816.22774.jhb@freebsd.org> <CAGdae7Yum_MP99kSK1Xi8z02APnZPoXFKR22fTuE5tiuorYMhw@mail.gmail.com>
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I suspected the hardware hence installed Linux and cross verified that Linux is working fine. /Venkat On Thu, Jun 21, 2012 at 6:20 PM, Venkat Duvvuru <venkatduvvuru.ml@gmail.com>wrote: > While I'm able to ping to the machine..every command on the current active > session is sluggish infact doesn't complete, unable to open another ssh > session..an already opened ssh session doesn't react which is running > "systat -vmstat"... > > The only thing I could do is to successfully complete "top -P" command > once..even top hung for the second time. > > /Venkat > > > On Thu, Jun 21, 2012 at 5:46 PM, John Baldwin <jhb@freebsd.org> wrote: > >> On Thursday, June 21, 2012 5:47:48 am Venkat Duvvuru wrote: >> > John - Thanks for the reply. >> > >> > All the CPUs are ~100% idle. I don't see any interrupt storm on any of >> the >> > irqs (vmstat -i). >> > >> > One observation I made is that I see messages like these in dmesg >> > >> > ===> mem >> 0xfaf60000-0xfaf7ffff,0xfaf40000-0xfaf5ffff,0xfaf1c000-0xfaf1ffff >> > irq 40 at device 0.1 on pci6 >> > >> > Looking at the irq value I think it is the INTx irq range which >> shouldn't >> > have probably got allocated as the device is msix capable and there are >> > vectors allocated for these devices in the range (256-380). >> > >> > Could this be a problem? >> >> No, that line is output before the driver's attach routine is run, so it >> will >> always show INTx IRQ value even if it isn't used. >> >> > The scenario where I am hitting this problem is a setup with 4 NICs, >> each >> > NIC with two ports and each port using up 4 msix vectors. The system is >> > fine till some ports are up but once I ifup the 5th port, the system >> > becomes sluggish. >> > >> > I'm not sure whether all the 30 vectors are from a single cpu..I don't >> know >> > how to get that information. >> >> Unfortunately there isn't an easy way. I have this gdb script which can >> display it from kgdb on x86: >> >> define irqs >> set $e = event_list->tqh_first >> while ($e != 0) >> if ($e->ie_source != 0 && $e->ie_handlers.tqh_first != 0) >> set $src = (struct intsrc *)$e->ie_source >> if ($src->is_pic->pic_enable_source == &ioapic_enable_source) >> set $_cpu = ((struct ioapic_intsrc *)$src)->io_cpu >> else >> if ($src->is_pic->pic_enable_source == &msi_enable_source) >> set $_cpu = ((struct msi_intsrc *)$src)->msi_cpu >> else >> set $_cpu = 0 >> end >> end >> printf "CPU %d: %s\n", $_cpu, $e->ie_fullname >> end >> set $e = $e->ie_list.tqe_next >> end >> end >> >> document irqs >> Dump list of IRQs with associated CPU. >> end >> >> However, unless the driver is using BUS_BIND_IRQ() or you are using >> cpuset -x, >> the interrupts should be round-robin assigned among CPUs. >> >> What exactly do you mean by sluggish? Trying to interact with the box >> over >> SSH is sluggish? Is there a change in RTT if you are pinging the box, is >> there a change in performance of TCP or UDP streams to/from the box? >> >> -- >> John Baldwin >> > >
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