Re: [RFC 00/14] perf tools: Introduce new 'ftrace' command

From: Namhyung Kim
Date: Thu Apr 25 2013 - 01:54:00 EST

On Wed, 24 Apr 2013 19:15:19 +0800, zhangwei wrote:
> On 2013/4/24 17:52, Namhyung Kim wrote:
>> I think it'd be great if perf trace can cover both of kernel and user
>> spaces. But function tracing in userspace looks impossible IMHO.
>> So how about changing perf trace to receive proposed sub-commands
>> (live/record/show/report) and following options:
>> --kernel:: do ftrace (for kernel functions)
>> --syscall:: do system call tracing (what perf trace does now)
> "--kernel" make me think it's will trace all event tracepoints, not only ftrace.

Well, I'm not sure what's the right name. --kernel-function?

> for "--syscall" option, I always think we should enhance syscall tracing more than now,
> like use annotate info when parse syscall event in perf, as other tracepoint does.
> we also need read filename user string in kernel space when open syscall tracepoint hit,
> record in, then perf parse it. After these functionality is implemented,
> we will don't need a separate syscall tracing tool in perf any more,
> just use: perf record -e "syscalls:" -a

It's a different story. But I do think it'd better if there's a way to
see some of userspace strings like this.

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