linux-trace-devel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Joel Fernandes <joelaf@google.com>,
	"Yordan Karadzhov (VMware)" <y.karadz@gmail.com>,
	Linux Trace Devel <linux-trace-devel@vger.kernel.org>
Subject: Re: Instructions for clock sync for tracing host/guest
Date: Mon, 26 Apr 2021 15:59:55 +0300	[thread overview]
Message-ID: <CAPpZLN48S2M33sBR8tV4e1Wr1tHKj9rN0gb52nh3cbX_KBbGbw@mail.gmail.com> (raw)
In-Reply-To: <20210426084408.581364d9@gandalf.local.home>

On Mon, Apr 26, 2021 at 3:44 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Mon, 26 Apr 2021 13:58:18 +0300
> Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:
>
> > On Fri, Apr 23, 2021 at 11:37 AM Joel Fernandes <joelaf@google.com> wrote:
> > >
> > > Apologies for the top post as I'm on Gmail mobile and only half awake at 4.30am.  I should check but can we just scrape the crosvm PIDs from the host trace itself ? The vCPU threads are in scheduler events in the host trace. Of course that wouldn't work if we don't have events. Let me know if that works for you or if I should find another way.
> > >
> > > By the way if sync is supposed to fall back to the ptp algo, why did it not fallback for me?
> >
> > Because of a bug in the code. It assumes if KVM is detected, then qemu
> > is used to run the VMs.
> >
>
> We need to find a way to do this without qemu. It's only the thread mapping
> that is missing here, nothing else. And KVM sync should still work.

The problem is to find the VM specific directory in the KVM debugfs,
where the VM TSC parameters are. The name of the directory is
/sys/kernel/debug/kvm/<some PID>-<number>/
The PID is the qemu process which runs the VM. I wonder how it looks in crosvm ?

[ ... ]




--
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

  reply	other threads:[~2021-04-26 13:00 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CAJWu+opJEtyXyhYnKL1iNzhfSCYRZN4PD50igckVvQV8416HEQ@mail.gmail.com>
     [not found] ` <CAPpZLN5pTxjnrQ=x0Kq7sGko+GSVv5gPTjSgETvO9kX1hgNCpQ@mail.gmail.com>
     [not found]   ` <20210418080435.3c3e2d24@oasis.local.home>
     [not found]     ` <CAJWu+oqG9T5v_2q+crsrsPe9GMcG0OSW7kcZ5ea=r1L07WKZJA@mail.gmail.com>
     [not found]       ` <CAPpZLN7MDoFYaJZG1+_4gUpYwt2RfAMfB=BDvGYch2eOfS342Q@mail.gmail.com>
     [not found]         ` <CAJWu+oosbOV=cigwfkNBLSpaMt3RExWLap3u+4G7pkYqQy_EXw@mail.gmail.com>
     [not found]           ` <CAPpZLN7=e+TL5WY7RKAo9Hm6AJGDygneqUWwoNnZexx+=KrxsQ@mail.gmail.com>
     [not found]             ` <CAJWu+op2bU+-z6W_+XB0v2g__oGXj8Be2WWDg36E9uaCjNp+HA@mail.gmail.com>
     [not found]               ` <CAJWu+orm+tm3C=MSF=p9eC1qgfE_pXzA2B0CiXgVXFemVRiVtA@mail.gmail.com>
     [not found]                 ` <CAJWu+opzT20OprG-8L_Lvv2DaJzF-ROaKnEWX8wjrbagPpwVzA@mail.gmail.com>
     [not found]                   ` <CAJWu+oqJk+BE2q=CjtAZJko-kJCS0Kyqwor_FVM3fu-X-rRRkg@mail.gmail.com>
     [not found]                     ` <20210422153845.3e6e9304@gandalf.local.home>
     [not found]                       ` <CAJWu+ooTVfprhd49__0H_61Fz_rSQA53n-VM6e1eEr8cTZ5aYQ@mail.gmail.com>
     [not found]                         ` <20210422154830.52f3e4f5@gandalf.local.home>
     [not found]                           ` <CAJWu+oqYWv5OHTLrC+oa7Y+LOe7AHumhtyVP8TC2LkK2=_JjPA@mail.gmail.com>
     [not found]                             ` <20210422160313.2eee1f77@gandalf.local.home>
     [not found]                               ` <CAJWu+ooZ9UptDBdii7dj=ui7dhiseOqZJE1CqMhP-Zy98QueXA@mail.gmail.com>
     [not found]                                 ` <CAJWu+opsWVBDA8R-wVhhn2G_6h1LsMwzRDE=gMruZpFG+AH5zQ@mail.gmail.com>
     [not found]                                   ` <CAJWu+oo8W9TVexZhhOs4P-DW1bH5DSjAzuV8QZMxvt9XHbRnJg@mail.gmail.com>
2021-04-23  8:16                                     ` Instructions for clock sync for tracing host/guest Tzvetomir Stoyanov
     [not found]                                       ` <CAJWu+orjdLAdcUJKWj6f8gUtXUzBcvJEPeKjtVZ7P+EpiptF0w@mail.gmail.com>
2021-04-23 11:33                                         ` Steven Rostedt
2021-04-23 15:49                                           ` Joel Fernandes
2021-04-26 10:58                                         ` Tzvetomir Stoyanov
2021-04-26 12:44                                           ` Steven Rostedt
2021-04-26 12:59                                             ` Tzvetomir Stoyanov [this message]
2021-04-26 14:11                                               ` Dario Faggioli
2021-04-26 14:51                                                 ` Steven Rostedt
2021-04-26 15:02                                                   ` Tzvetomir Stoyanov
2021-04-26 15:31                                                     ` Steven Rostedt
2021-04-26 15:37                                                       ` Steven Rostedt
2021-04-26 15:44                                                       ` Dario Faggioli
2021-04-26 15:38                                                     ` Dario Faggioli
2021-04-26 15:50                                                       ` Steven Rostedt
2021-04-26 16:10                                                         ` Dario Faggioli
2021-04-25 18:29                                       ` Steven Rostedt
2021-04-26 10:39                                         ` Tzvetomir Stoyanov
2021-04-26 12:56                                           ` Steven Rostedt
2021-04-26 13:24                                             ` Dario Faggioli
2021-04-26 13:51                                               ` Tzvetomir Stoyanov

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=CAPpZLN48S2M33sBR8tV4e1Wr1tHKj9rN0gb52nh3cbX_KBbGbw@mail.gmail.com \
    --to=tz.stoyanov@gmail.com \
    --cc=joelaf@google.com \
    --cc=linux-trace-devel@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=y.karadz@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).