Messages in this thread | | | Date | Fri, 24 Apr 2015 12:49:05 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] enforce function inlining for hot functions |
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On Thu, 23 Apr 2015 23:40:01 +0200 Hagen Paul Pfeifer <hagen@jauu.net> wrote:
> GCC inlining heuristics are sometimes quizzical. Especially with inline > assembler constructs GCC seems to have issues. A allyesconfig show a rather > long list of functions where GCC inlining decisions are questionable (not > inlined).
I can't reproduce this with either gcc-4.8.2 or gcc-4.4.4. The patch makes zero difference to `size vmlinux' and a bit of poking around with nm doesn't show any out-of-lined versions of the functions you identify.
So. More details, please. How to demonstrate this, gcc versions, etc.
> Furthermore, because the functions are declared with static > linkage each function is copied n times - and n can be rather high: > > atomic_inc: 544 duplicates > rcu_read_unlock: 453 duplicates > rcu_read_lock: 383 duplicates > get_dma_ops: 271 duplicates > arch_local_irq_restore: 258 duplicates > atomic_dec: 215 duplicates > kzalloc: 185 duplicates > cpumask_check: 157 duplicates > test_and_set_bit: 156 duplicates > cpumask_next: 146 duplicates > list_del: 131 duplicates > kref_get: 126 duplicates
That's pretty pathetic.
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