Hi Jin Yao,
Sorry I haven't commented until now, but it got lost in the flood of
Just a few nit-picks below ...
Jin Yao <yao.jin@xxxxxxxxxxxxxxx> writes:
It is often useful to know the branch types while analyzing branchMost of the code and doc uses "branch" but then a few these are called
data. For example, a call is very different from a conditional branch.
Currently we have to look it up in binary while the binary may later
not be available and even the binary is available but user has to take
some time. It is very useful for user to check it directly in perf
Perf already has support for disassembling the branch instruction
to get the x86 branch type.
To keep consistent on kernel and userspace and make the classification
more common, the patch adds the common branch type classification
"jump". Can we just stick with "branch"?
PERF_BR_NONE : unknowneg:
PERF_BR_JCC : conditional jump
PERF_BR_JMP : jump
PERF_BR_IND_JMP : indirect jump
PERF_BR_COND : conditional branch
PERF_BR_UNCOND : unconditional branch
PERF_BR_IND : indirect branch
PERF_BR_CALL : callI'm not sure what that means, I'm guessing on x86 it means someone
PERF_BR_IND_CALL : indirect call
PERF_BR_RET : return
PERF_BR_SYSCALL : syscall
PERF_BR_SYSRET : syscall return
PERF_BR_IRQ : hw interrupt/trap/fault
PERF_BR_INT : sw interrupt
executed "int" ?
Is that sufficiently useful to use up a bit? I think we only have 3
PERF_BR_IRET : return from interruptWhat is a "not generic far branch" ?
PERF_BR_FAR_BRANCH: not generic far branch type
I don't know what that would mean on powerpc for example.
I think the only thing we have on powerpc that's commonly used and that
isn't covered above is branches that decrement a loop counter and then
branch based on the result.
It might be nice if we could separate those out from other conditional
branches. Whether it's worth using a bit for I'm not sure. Do other
arches have something similar?
Those branches do tend to be "backward conditional", so that may be
sufficient. But backward conditional also includes if bodies that have
been moved out of line and then branch back to the main body of the