KVM SnowRidge Processor Trace v4

[Paul Lai]

The PEBS(Processor Event Based Sampling) facility allows software to profile workload behavior by periodically capturing machine state, memory access information and other groups of architectural information. In native systems, PEBS uses a debug store mechanism to store a set of architectural state information for the processor and we need to specify a linear pages for the output buffer which must be pinned to physical pages. In virtualized systems, pinning the platform physical pages for the output buffer is difficult.
 PT V4 provide a method to format PEBS sampling data to new type of trace packet and output to Intel Processor Trace buffer. This depend on PT-VMX(Enabling use of EPT to redirect PT output)which enabled in ICX platform.
 Need modify in KVM and Qemu.

Intel Processor Trace v4 task list:
◾PT VMX which is done and in upstream phase, and need more review and update effort
◾PEBS via PT on SNR. It's new added task, which target to ww48
◾PT PEBS/EMON integration. This feature allows PEBS data to be written into PT output channel, leveraging PT Virtualization work for PEBS.
◾cpuid support and context switch
◾Support host-guest mode and system mode
 More Open feature includes Live Migration support and LBR support

Upstream target 5.2
Target Release: 19.10

[Christian Ehrhardt  (paelzer)]

Hi,
title says KVM, but the bug is only against xen so far.

Will this need an "qemu (ubuntu)" and/or "linux (ubuntu)" task as well?

- kernel 4.20 is listed so I assume the latter.
- Comment mentions Qemu, will it be in 2.13 or are changes needed on top?

[Christian Ehrhardt  (paelzer)]

This is another bug filed against xen, but then mentioning qemu and kernel.
There was no feedback since my question a few months ago, but xen as the only target package makes no sense it seems.
I added bug tasks accordingly.

[Christian Ehrhardt  (paelzer)]

@Quanxian - as usual let us know when you have mailing list posts or even better commits in the kernel and qemu that we can use to track and integrate this.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1782207

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Christian Ehrhardt  (paelzer)]

Feature request that does not need the kernel logs the bot asks for