Messages in this thread | | | Date | Fri, 23 Mar 2018 12:50:16 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 0/3] [RFC] init, tracing: Add initcall trace events |
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On Fri, 23 Mar 2018 11:02:41 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> A while ago we had a boot tracer. But it was eventually removed: > commit 30dbb20e68e6f ("tracing: Remove boot tracer"). > > The rational was because there is already a initcall_debug boot option > that causes printk()s of all the initcall functions.
"rationale" :)
> The problem with the initcall_debug option is that printk() is awfully slow, > and makes it difficult to see the real impact of initcalls. Mainly because > a single printk() is usually slower than most initcall functions.
Not understanding this. We do it correctly:
calltime = ktime_get(); ret = fn(); rettime = ktime_get();
so the displayed initcall timing is independent of the printk() execution time?
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