Messages in this thread | | | Date | Mon, 09 Oct 2017 16:17:08 -0700 (PDT) | Subject | Re: [PATCH v2] net/core: Fix BUG to BUG_ON conditionals. | From | David Miller <> |
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From: Alexei Starovoitov <alexei.starovoitov@gmail.com> Date: Mon, 9 Oct 2017 16:06:20 -0700
>> For these archs, wouldn't it then be more efficient to use BUG_ON >> rather than BUG()? > > why more efficient? any data to prove that?
It can completely eliminate a branch.
For example on powerpc if you use BUG() then the code generated is:
test condition branch_not_true 1f unconditional_trap 1:
Whereas with BUG_ON() it's just:
test condition trap_if_true
Which is a lot better even when the branches in the first case are well predicted.
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