Hi,
(adding back lttng-dev in CC for the benefit of others)
Whenever possible, we try to augment the trace data with such additional
information at post-processing, because capturing it at run-time repeatedly
ends
up being costly.
The lttng-analyses project contains state tracker which augment the trace data
with mapping from file descriptor to corresponding file names (see
lttnganalyses/linuxautomaton/io.py).
I'm not sure if the Trace Compass project models this mapping between file
descriptors and their
associated file, but if not, it would be an *extremely* useful addition.
lttng-modules already dumps the information needed to create that model:
- lttng_statedump_file_descriptor dumps all existing file descriptors for all
processes,
- a few system calls (open, dup, dup2, dup3, close, clone(see CLONE_FILES
flag), fork,
fcntl(cmd==F_DUPFD)) allow tracking the file descriptor table state changes
during the trace.
Thanks,
Mathieu
- On Nov 25, 2019, at 7:36 PM, 杨海 wrote:
> Hi Mathieu
> Thanks for quick response. Here let me give an example. For syscalls open,
> LTTng
> output filename in entry_open and output fd as ret in exit_open. It would be
> desired to output both filename and fd so we can correlate them.
> I am not sure whether there is a configuration that we can have the richest
> output regarding to syscalls.
> If not, we can modify lttng-modules to output what we need. Or any other
> recommendation?
> Regards
> Hai
> --
> 该邮件从移动设备发送
> --原始邮件--
> 发件人："Mathieu Desnoyers ";
> 发送时间：2019年11月20日(星期三) 晚上10:32
> 收件人："杨海" ;
> 抄送："lttng-dev ";
> 主题：Re: [lttng-dev] documentation about CTF event payload
> ---
> For the system call payload documentation, you might want to refer to the
> Linux
> system call
> man pages.
> For internal kernel tracepoints like sched_switch, there is no documentation
> of
> the meaning of
> each field at the moment. This state is the same as the upstream Linux kernel
> trace event. You'll
> have to figure it out on your own. Documenting each field of the ~500-1000
> Linux
> kernel tracepoints
> is no small task.
> Thanks,
> Mathieu
> - On Nov 19, 2019, at 9:25 PM, 杨海 wrote:
>> To be more specific, I suppose we can refer to
>> instrumentation\syscalls\3.10.0-rc7\x86-64-syscalls-3.10.0-rc7 for the
>> payload
>> format of syscall event. Is it exactly in the CTF syscall event?
>> Regards
>> Hai
>> -- Original --
>> From: "杨海";
>> Date: Mon, Nov 18, 2019 09:54 AM
>> To: "lttng-dev";
>> Subject: documentation about CTF event payload
>> Hi
>> As LTTng generated CTF and babeltrace parse it, we have the output as
>> attached.
>> We saw events such as sched_switch, but the payload cannot be understood
>> easily. Where we can find the document to explain the LTTng payload and
>> parameters?
>> Regards
>> Hai
>> ___
>> lttng-dev mailing list
>> lttng-dev@lists.lttng.org
>> https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
> --
> Mathieu Desnoyers
> EfficiOS Inc.
> http://www.efficios.com
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
___
lttng-dev mailing list
lttng-dev@lists.lttng.org
https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
