svn commit: r250215 - stable/9/lib/libc/locale

[Sergey Kandaurov]

On 4 May 2013 18:21, Andrey Chernov <ache at freebsd.org> wrote:
> On 04.05.2013 16:03, Sergey Kandaurov wrote:
>>> BTW, I don't run tests and look in asm code for sure, but it seems
>>> property[0] == p[0] is unneeded because almost every compiler tries to
>>> inline strcmp().
>>
>> Doesn't seem so (in-lining), see below.
>
> Yes, system's GNU cc don't inline strcmp() but inlines memcmp():
>  repz
>  cmpsb
> I don't have clang nearby right now to test what it does.

I've checked gcc46 and clang3.2, and they behave similarly (poor).
It's worth to note that inlined memcmp didn't help with performance
relative to strcmp().

note2  - it's surprising that only base gcc inlined memcmp. This explains
the difference between base gcc and {gcc46, clang} in the table below.

1 - base gcc 4.2
2 - gcc46
3 - base clang 3.2

a - if (property[0] == p[0] && strcmp(property, p) == 0)
b - if (property[0] == p[0] && memcmp(property, p, *len2) == 0)
c - if (memcmp(property, p, *len2) == 0)

Time spend for 2097152 wctype() calls for each of wctype property

         1a     2a      3a      1b      2b      3b      1c      2c      3c
alnum    0.034  0.036   0.034   0.049   0.071   0.073   0.046   0.068   0.069
alpha    0.045  0.049   0.046   0.111   0.156   0.158   0.107   0.153   0.154
blank    0.037  0.041   0.038   0.053   0.075   0.079   0.153   0.224   0.223
cntrl    0.039  0.044   0.042   0.058   0.078   0.081   0.206   0.300   0.301
digit    0.039  0.044   0.043   0.059   0.080   0.085   0.259   0.378   0.378
graph    0.043  0.049   0.050   0.061   0.082   0.087   0.313   0.455   0.455
lower    0.044  0.049   0.051   0.062   0.085   0.090   0.365   0.532   0.533
print    0.048  0.054   0.059   0.067   0.088   0.092   0.419   0.610   0.610
punct    0.060  0.067   0.103   0.127   0.183   0.211   0.477   0.692   0.692
space    0.053  0.059   0.067   0.072   0.092   0.097   0.525   0.764   0.765
upper    0.054  0.059   0.068   0.074   0.094   0.100   0.578   0.841   0.842
xdigit   0.060  0.066   0.077   0.079   0.099   0.106   0.635   0.922   0.985
ideogram 0.068  0.074   0.084   0.087   0.089   0.094   0.695   0.986   0.985
special  0.098  0.104   0.113   0.169   0.210   0.212   0.753   1.116   1.118
phonogram 0.136 0.156   0.187   0.240   0.285   0.325   0.815   1.181   1.183
rune     0.064  0.070   0.087   0.099   0.104   0.113   0.842   1.293   1.283

-- 
wbr,
pluknet