Re: [vfio-users] Brutal DPC Latency - how is yours? check it please and report back

Tue, 29 Dec 2015 08:46:02 -0800

I noticed that attaching a DVD-Drive from the host leads to HUGE delays. I had attached my /dev/sr0 to the guest and even without a DVD in the drive this was causing huge lag about once per second. 

Best regards
Michael

Am 28.12.2015 um 19:30 schrieb rndbit:

4000μs-16000μs here, its terrible.
Tried whats said on https://lime-technology.com/forum/index.php?topic=43126.15 
Its a bit better with this:

  <vcpu placement='static'>4</vcpu>
  <cputune>
    <vcpupin vcpu='0' cpuset='4'/>
    <vcpupin vcpu='1' cpuset='5'/>
    <vcpupin vcpu='2' cpuset='6'/>
    <vcpupin vcpu='3' cpuset='7'/>
    <emulatorpin cpuset='0-3'/>
  </cputune>
I tried /isolcpus/ but it did not yield visible benefits. /ndis.sys/ is big offender here but i dont really understand why. Removing network interface from VM makes /usbport.sys/ take over as biggest offender. All this happens with /performance/ governor of all cpu cores:
echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor >/dev/null
Cores remain clocked at 4k mhz. I dont know what else i could try. Does anyone have any ideas..? 

On 2015.10.29 08:03, Eddie Yen wrote:
I tested again with VM reboot, I found that this time is about 1000~1500μs. Also I found that it easily get high while hard drive is loading, but only few times. 

Which specs you're using? Maybe it depends on CPU or patches.
2015-10-29 13:44 GMT+08:00 Blank Field <ihatethisfi...@gmail.com <mailto:ihatethisfi...@gmail.com>>: 

    If i understand it right, this software has a fixed latency error
    of 1 ms(1000us) in windows 8-10 due to different kernel timer
    implementation. So i guess your latency is very good.

    On Oct 29, 2015 8:40 AM, "Eddie Yen" <missile0...@gmail.com
    <mailto:missile0...@gmail.com>> wrote:

        Thanks for information! And sorry I don'r read carefully at
        beginning message.

        For my result, I got about 1000μs below and only few times
        got 1000μs above when idling.

        I'm using 4820K and used 4 threads to VM, also  I set these 4
        threads as 4 cores in VM settings.
        The OS is Windows 10.

        2015-10-29 13:21 GMT+08:00 Blank Field
        <ihatethisfi...@gmail.com>:

            I think they're using this:
            www.thesycon.de/deu/latency_check.shtml
            <http://www.thesycon.de/deu/latency_check.shtml>

            On Oct 29, 2015 6:11 AM, "Eddie Yen"
            <missile0...@gmail.com> wrote:

                Sorry, but how to check DPC Latency?

                2015-10-29 10:08 GMT+08:00 Nick Sukharev
                <nicksukha...@gmail.com>:

                    I just checked on W7 and I get 3000μs-4000μs one
                    one of the guests when 3 guests are running.

                    On Wed, Oct 28, 2015 at 4:52 AM, Sergey Vlasov
                    <ser...@vlasov.me> wrote:

                        On 27 October 2015 at 18:38, LordZiru
                        <lordz...@gmail.com> wrote:

                            I have brutal DPC Latency on qemu, no
                            matter if using pci-assign or vfio-pci or
                            without any passthrought,

                            my DPC Latency is like:
                            10000,500,8000,6000,800,300,12000,9000,700,2000,9000
                            and on native windows 7 is like:
                            20,30,20,50,20,30,20,20,30

                        InWindows 10 guest I constantly have red bars
                        around 3000μs (microseconds), spiking
                        sometimes up to 10000μs.


                            I don't know how to fix it.
                            this matter for me because i are using
                            USB Sound Card for my VMs,
                            and i get sound drop-outs every 0-4 secounds


                        That bugs me a lot too. I also use an
                        external USB card and my DAW periodically
                        drops out :(

                        I haven't tried CPU pinning yet though. And
                        perhaps I should try Windows 7.


                        _______________________________________________
                        vfio-users mailing list
                        vfio-users@redhat.com
                        <mailto:vfio-users@redhat.com>
                        https://www.redhat.com/mailman/listinfo/vfio-users



                    _______________________________________________
                    vfio-users mailing list
                    vfio-users@redhat.com <mailto:vfio-users@redhat.com>
                    https://www.redhat.com/mailman/listinfo/vfio-users



                _______________________________________________
                vfio-users mailing list
                vfio-users@redhat.com <mailto:vfio-users@redhat.com>
                https://www.redhat.com/mailman/listinfo/vfio-users





_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users




_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users



_______________________________________________
vfio-users mailing list
vfio-users@redhat.com
https://www.redhat.com/mailman/listinfo/vfio-users

Reply via email to