Re: [PATCH] perf tools: Add support for pinned modifier

From: Michael Ellerman
Date: Thu Jul 25 2013 - 08:53:36 EST


On Thu, 2013-07-25 at 13:04 +0200, Peter Zijlstra wrote:
> On Wed, Jul 24, 2013 at 12:26:42PM +1000, Michael Ellerman wrote:
> >
> > I would have used "p" obviously, but that's taken. Are folks happy that
> > "P" is sufficiently different from "p"? I couldn't think of anything
> > better.
>
> I've seen proposals where 'P' is used for the max 'p' level :/

Hmm, OK.

So 'p' is for precise, which maps onto a 2 bit field in
perf_event_attr.precise_ip.

No 'p' modifier means precise_ip = 0, so the max value of 3 would be
'ppp' right?

We don't use 'p' so I have no idea how often it's used and whether
typing 'ppp' is going to be a major pain for people.

> But yes, vexing situation.

Quite. Nothing jumps out as an obvious alternative, including any of the
symbols.

So how about 'D'.

Because it makes a smiley face:

$ perf stat -e cycles:D

And having perf smile at you can't be a bad thing.

cheers



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