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From: "Yordan Karadzhov (VMware)" <>
To: Steven Rostedt <>,
	"Tzvetomir Stoyanov (VMware)" <>
Subject: Re: [PATCH 0/2] KernelShark2.0: Use libtracefs APIs to access tracefs
Date: Mon, 9 Mar 2020 11:10:30 +0200
Message-ID: <> (raw)
In-Reply-To: <20200306151356.4bbeef14@gandalf.local.home>

On 6.03.20 г. 22:13 ч., Steven Rostedt wrote:
> On Fri,  6 Mar 2020 11:29:00 +0200
> "Tzvetomir Stoyanov (VMware)" <> wrote:
>> From: "Tzvetomir (VMware)  Stoyanov" <>
>> The tracefs library provides APIs for accessing files from tracefs.
>> The library is part of trace-cmd, it is installed as part of trace-cmd
>> installation. KernelShark uses some of those APIs and must be linked with
>> the library
>> Tzvetomir (VMware)  Stoyanov (2):
>>    KernelShark2.0: Link KernelShark to libtracefs
>>    KernelShark2.0: Use libtracefs APIs to access tracefs
> I added these patches to the latest kernelshark-2.0 and it still doesn't
> work for me. I did a little debugging, and noticed that it fails while
> reading the guest trace.dat file with:
> plugin "kvm_combo" failed to initialize on stream /tmp/trace-host-Fedora21.
> It seems to require that the guest trace.dat file has kvm events?

Hi Steven,

Yes it will fail to initialize in the guest's file if it does not 
contain kvm events and this is normal. The plugin only draws the 
additional graphical elements associated with kvm_entry and kvm_exit 
events. So nothing will be plotted on top of the guest data.

The plugin itself has nothing to do with the synchronization of the 


> Note, as I build my guest kernel with a make localmodconfig, which disables
> all modules that are not necessary to boot the box, there is no kvm events
> there. I can see why the host may need them, but not the guest. I'll
> rebuild my guest kernel with kvm events and see if that solves this (but
> that shouldn't be the case).
> -- Steve

      parent reply index

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-06  9:29 Tzvetomir Stoyanov (VMware)
2020-03-06  9:29 ` [PATCH 1/2] KernelShark2.0: Link KernelShark to libtracefs Tzvetomir Stoyanov (VMware)
2020-03-06  9:29 ` [PATCH 2/2] KernelShark2.0: Use libtracefs APIs to access tracefs Tzvetomir Stoyanov (VMware)
2020-03-06 20:13 ` [PATCH 0/2] " Steven Rostedt
2020-03-06 22:34   ` Steven Rostedt
2020-03-09  9:17     ` Yordan Karadzhov (VMware)
2020-03-09 15:44       ` Steven Rostedt
2020-03-09 16:30         ` Steven Rostedt
2020-03-09  9:10   ` Yordan Karadzhov (VMware) [this message]

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