[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] trace: teach lttng backend to use format string
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH] trace: teach lttng backend to use format strings |
Date: |
Tue, 25 Mar 2014 14:49:42 +0000 |
User-agent: |
mu4e 0.9.9.6pre2; emacs 24.3.50.2 |
Stefan Hajnoczi <address@hidden> writes:
> On Mon, Mar 24, 2014 at 05:04:54PM +0000, address@hidden wrote:
>> From: Alex Bennée <address@hidden>
>>
>> This makes the UST backend pay attention to the format string arguments
>> that are defined when defining payload data. With this you can now
>> ensure integers are reported in hex mode if you want.
>>
>> Signed-off-by: Alex Bennée <address@hidden>
>> ---
>> scripts/tracetool/__init__.py | 13 +++++++++++--
>> scripts/tracetool/backend/ust.py | 16 ++++++++++++----
>> 2 files changed, 23 insertions(+), 6 deletions(-)
>
> How are strings handled, can LTTng copy them from the QEMU process'
> memory space?
lttng provides ctf_string for passing strings to the payload. But I
wouldn't expect to use them for the result of format string calculations
as that would defeat the point of the low impact tracing.
There are a number of trace-events that pass strings for various things.
I've not actually experimented with the output of any of them though.
>
> Stefan
--
Alex Bennée