Testing (perf analysis) with perf

[dimakuv]

Install TDX-kernel-specific perf

Get all the packages as specified in the "Linux Stacks" document. In the Linux packages directory, you can do:

$ find . -name "*linux-tools*.deb"

./build/ubuntu-22.04/intel-mvp-tdx-kernel/linux-tools-common_5.19.0-mvp15v2+4.tdx_all.deb
./build/ubuntu-22.04/intel-mvp-tdx-kernel/linux-tools-5.19.0-mvp15v2+4-generic_5.19.0-mvp15v2+4.tdx_amd64.deb
./build/ubuntu-22.04/intel-mvp-tdx-kernel/linux-tools-5.19.0-mvp15v2+4_5.19.0-mvp15v2+4.tdx_amd64.deb
./build/ubuntu-22.04/intel-mvp-tdx-kernel/linux-tools-host_5.19.0-mvp15v2+4.tdx_all.deb

Install manually all these packages (sudo dpkg -i package_file.deb).

Using perf stat

We'll use system-wide perf stat. For this, we need sudo rights.

• Start perf in one terminal: sudo -E perf stat -e 'kvm:*'
• Start the gramine-vm app in another terminal: gramine-vm helloworld
• After the app is done, stop perf by Ctrl-C

If we want to get the stats only on some part of the app execution (e.g., after the initialization phase), then start perf right-after the app is done with the init phase.

Links:

• https://www.linux-kvm.org/page/Perf_events
• https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_deployment_and_administration_guide/sect-troubleshooting-kvm_stat

Using perf kvm

• Start perf in one terminal: sudo -E perf kvm stat record
• Start the gramine-vm app in another terminal: gramine-vm helloworld
• After the app is done, stop perf by Ctrl-C

Now we can analyze via sudo perf kvm stat report.

Links:

• https://man7.org/linux/man-pages/man1/perf-kvm.1.html
• https://www.linux-kvm.org/page/Perf_events
• https://github.com/iovisor/bcc/blob/master/examples/tracing/kvm_hypercall.txt
• https://eastrivervillage.com/perf-kvm-to-profile-vm-exit/