[Patch] Step2: don't use _M_out_lim in filebuf, have filebuf non unified, etc...

[Paolo Carlini]

Nathan Myers wrote:

>>Anyway, *right now*, on my P4, for 9876
>>
>>1.990u 0.370s 0:02.37 99.5%     0+0k 0+0io 215pf+0w   (stdio unlocked)
>>1.480u 0.380s 0:01.94 95.8%     0+0k 0+0io 216pf+0w   (iostream)
>>    
>>
>I ran another benchmark, attached below, on several compilers
>on P3 and Opteron.  All builds are -O2.
>
Thanks Nathan. I can reproduce you results here, with my P4. Therefore I 
would be tempted to move right away sputc, sbumpc (and also, perhaps, 
sungetc and sputbackc).

An additional puzzling data point, however: have you tried moving _only_ 
sbumpc to std_streambuf.h vs moving both sbumpc and sputc?

Here, if both are moved 9876 regresses to the pre-patch performance...

Paolo.