[Bug libstdc++/19642] streaming doubles is very slow compared to sprintf

[joerg dot richter at pdv-fs dot de]

------- Additional Comments From joerg dot richter at pdv-fs dot de  2005-01-27 15:05 -------
With patch draft_19642_3 and count=1000000

$ time t > /dev/null
real   0,64
user   0,60
sys    0,01

$ time t cout > /dev/null
real   1,14
user   1,12
sys    0,00

Now its only 2 times slower than sprintf. Much better than the ~75 times before.

Also note, that when an other locale than "C" is in place the times also get 
better:

without patch: (count=100000)
real   28,27
user   6,34
sys    21,87

with:
real   5,66
user   1,89
sys    3,78

(sprintf:0,07s)

This case is still horrible slow, but 4-5 times better than before.

Good work so far, but I think the final solution is to avoid any frequent 
setlocale() calls.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19642