Messages in this thread | | | Date | Tue, 18 Nov 2014 08:55:39 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH V3 3/3] perf tools: Construct LBR call chain |
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On Tue, Nov 18, 2014 at 03:13:50PM +0900, Namhyung Kim wrote:
SNIP
> >> > + * in "from" register, while the callee is stored > >> > + * in "to" register. > >> > + * For example, there is a call stack > >> > + * "A"->"B"->"C"->"D". > >> > + * The LBR registers will recorde like > >> > + * "C"->"D", "B"->"C", "A"->"B". > >> > + * So only the first "to" register and all "from" > >> > + * registers are needed to construct the whole > >> stack. > >> > + */ > >> > >> Andi is using some sanity checks: > >> http://marc.info/?l=linux-kernel&m=141584447819894&w=2 > >> I guess this could be applied in here, once his patch gets in. > >> > > > > Are you suggesting me to remove the comments, > > or rebase the whole patch to Andi's patch once it's merged? > > > > The branch history in Andi's patch is different as the call stack, > > although they are both from LBR. > > Andi's branch history recording branch records for > > taken branches, interrupts, and exceptions. > > While the LBR call stack records for the call stack. > > Right. And branch history can overlap with normal callchains so > additional check in there is to remove duplication. While LBR call > stack is separated to user only so there should be no overlap.
hum, it seemed to me like the remove_loops function could be used for this one as well.. but anyway I meant that this can be introduced later after Andi's change gets in
thanks, jirka
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