Hi all,
I run some lengthy tests to measure cost of inlines in headers under
include/, simple coverage calculations yields to 89% but most of the
failed compiles are due to preprocessor cutting the tested block away
anyway. Test setup: v2.6.24-mm1, make allyesconfig, 32-bit x86,
gcc (GCC) 4.1.2 20070626 (Red Hat 4.1.2-13). Because one inline was
tested (function uninlined) at a time, the actual benefits of removing
multiple inlines may well be below what the sum of those individually
is (especially when something calls __-func with equal name).
Ok, here's the top of the list (10000+ bytes):
-110805 869 f, 198 +, 111003 -, diff: -110805 skb_put
-41525 2066 f, 3370 +, 44895 -, diff: -41525 IS_ERR
-36290 42 f, 197 +, 36487 -, diff: -36290 cfi_build_cmd
-35698 1234 f, 2391 +, 38089 -, diff: -35698 atomic_dec_and_test
-28162 354 f, 3005 +, 31167 -, diff: -28162 skb_pull
-23668 392 f, 104 +, 23772 -, diff: -23668 dev_alloc_skb
-22212 415 f, 130 +, 22342 -, diff: -22212 __dev_alloc_skb
-21593 356 f, 2418 +, 24011 -, diff: -21593 skb_push
-19036 478 f, 259 +, 19295 -, diff: -19036 netif_wake_queue
-18409 396 f, 6447 +, 24856 -, diff: -18409 __skb_pull
-16420 187 f, 103 +, 16523 -, diff: -16420 dst_release
-16025 13 f, 280 +, 16305 -, diff: -16025 cfi_send_gen_cmd
-14925 486 f, 978 +, 15903 -, diff: -14925 add_timer
-14896 199 f, 558 +, 15454 -, diff: -14896 sg_page
-12870 36 f, 121 +, 12991 -, diff: -12870 le_key_k_type
-12310 692 f, 7215 +, 19525 -, diff: -12310 signal_pending
-11640 251 f, 118 +, 11758 -, diff: -11640 __skb_trim
-11059 111 f, 293 +, 11352 -, diff: -11059 __nlmsg_put
-10976 209 f, 123 +, 11099 -, diff: -10976 skb_trim
-10344 125 f, 462 +, 10806 -, diff: -10344 pskb_may_pull
-10061 300 f, 1163 +, 11224 -, diff: -10061 try_module_get
-10008 75 f, 341 +, 10349 -, diff: -10008 nlmsg_put
~250 are in 1000+ bytes category and ~440 in 500+. Full list
has some entries without number because given config doesn't
build them, and therefore nothing got uninlined, and the missing
entries consists solely of compile failures, available here:
http://www.cs.helsinki.fi/u/ijjarvin/inlines/sorted
I made some patches to uninline couple of them (picked mostly
net related) to stir up some discussion, however, some of them
are not ready for inclusion as is (see patch descriptions).
The cases don't represent all top 8 cases because some of the
cases require a bit more analysis (e.g., config dependant,
comments about gcc optimizations).
The tools I used are available here except the site-specific
distribute machinery (in addition one needs pretty late
codiff from Arnaldo's toolset because there were some inline
related bugs fixed lately):
http://www.cs.helsinki.fi/u/ijjarvin/inline-tools.git/
I'm planning to run similar tests also on inlines in headers that
are not under include/ but it requires minor modifications to
those tools.
--
i.