Hi Stefano,
On Fri, Mar 19, 2021 at 12:08 PM Stefano De Venuto
<stefano.devenuto99@xxxxxxxxx> wrote:
>
> Hello,
>
> On 3/15/21 7:18 AM, Tzvetomir Stoyanov (VMware) wrote:
> > Basic infrastructure for host - guest timestamp synchronization and a
> > PoC implementation of PTP-like and KVM algorithms.
> I'm trying to make some analysis on traces generated by host and guest,
> so I applied this series and the related dependencies.
>
> However, when the KVM algorithm is used, the merging process
> of the two traces doesn't seem to happen properly.
>
> The output of `trace-cmd report -i trace.dat -i trace-tumbleweed.dat` is:
>
> trace.dat: cpus=4
> trace-tumbleweed.dat: cpus=1
> trace.dat: sleep-23948 [002]61124758463654:
> write_msr: c0000100, value 7f35092875c0
> trace.dat: <idle>-0 [000]61124760841508:
> write_msr: c0000100, value 7f6136b75640
> trace.dat: CPU 0/KVM-1640 [000]61124760851620:
> write_msr: c0011020, value 40000000000000
> trace.dat: CPU 0/KVM-1640 [000]61124760861778:
> read_msr: c0000101, value ffff9b1b76c00000
> trace.dat: CPU 0/KVM-1640 [000]61124760862832:
> read_msr: c0000081, value 23001000000000
> trace.dat: CPU 0/KVM-1640 [000]61124760864347:
> read_msr: c0000082, value ffffffffb5400010
> trace.dat: CPU 0/KVM-1640 [000]61124760865225:
> read_msr: c0000083, value ffffffffb5401670
> .
> .
> .
> trace-tumbleweed.dat: IPC I/O Parent-4313 [000]8446232460209009653:
> write_msr: c0000100, value 7f94535c7640
> trace-tumbleweed.dat: IPC I/O Child-4503 [000]8446348845232796661:
> write_msr: c001011f, value 4
> trace-tumbleweed.dat: IPC I/O Child-4503 [000]8447532508154803189:
> write_msr: c0000100, value 7f945e8d5780
> trace-tumbleweed.dat: <idle>-0 [000]8452336523564659701:
> write_msr: c001011f, value 0
> trace-tumbleweed.dat: <idle>-0 [000]8452515224268944373:
> write_msr: 6e0, value 731478a3bf62
> trace-tumbleweed.dat: <idle>-0 [000]8452610851715789813:
> write_msr: 6e0, value 731478968f37
> trace-tumbleweed.dat: <idle>-0 [000]8555757214338495477:
> write_msr: 6e0, value 731478853ec1
> trace-tumbleweed.dat: <idle>-0 [000]8555904475882173429:
> write_msr: 6e0, value 7314778a60e8
> trace-tumbleweed.dat: kworker/0:1-7351 [000]8556355589182174197:
> write_msr: c0000100, value 7f8373573740
>
> The TimeShift information is inside the guest trace file,
> so I think this is not a transfer problem.
>
> I also tried to remove the last patch, the one related to the KVM clock,
> in order to use PTP and the two traces are merged correctly.
>
> The commands used to record are:
>
> Host:
> # trace-cmd record -C x86-tsc -e kvm:* -e msr:* -A tumbleweed:823 -e
> msr:* -C x86-tsc sleep 1
The guest trace clock is set automatically as the host, so this
command should be enough:
# trace-cmd record -C x86-tsc -e kvm:* -e msr:* -A tumbleweed:823 -e
msr:* sleep 1
>
> Guest:
> # echo x86-tsc > /sys/kernel/tracing/trace_clock
There is no need to set manually the guest clock, it will be
overwritten by trace-cmd agent.
> # trace-cmd agent
>
> Am I doing something wrong?
All your commands and workflow look good, nothing wrong.
>
> If necessary, I can provide more info about my setup, or do more tests.
Yes, please can you send me both host and guest trace files ?
Also, it will be useful to send me the content of the KVM debug files:
/sys/kernel/debug/kvm/<guest ID>/vcpu<*>/tsc-offset
>
>
> Thanks and Regards,
>
> Stefano
Thanks for testing this code!
--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center
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