Re: [PATCH 0/9] perf: Adding better precise_ip field handling

[Gleb Natapov]

On Mon, May 13, 2013 at 09:43:13PM +0200, Ingo Molnar wrote:
> Note that at least for user-space, REP MOVS is getting rarer. libc uses 
> SSE based memcpy/memset variants - which is not miscounted by PEBS. The 
> kernel still uses REP MOVS - but it's a special case because it cannot 
> cheaply use vector registers.
> 
> The vast majority of code gets measured by cycles:pp more accurately than 
> cycles.
> 
> We could try and see how many people complain. It's not like it's hard to 
> undo such a change of the default event?
> 
People may optimize for a wrong case instead of complaining. There is
nothing that obviously broken, only if you know what to look for the
brokenness can be seen.

--
			Gleb.
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