Re: [PATCH glibc] Hurd: Fix definition of `PAGE_COPY_THRESHOLD'

[Justus Winter]

Quoting Justus Winter (2014-12-10 12:59:43)
> Somewhat less synthetic:
> 
> % bash do_pipebench.bash
> Piping 1024 MByte from zero to null.
> (dd if=zero bs=X count=overall/X | dd of=null bs=X)
> 4096      8192     12288     16384     32768     65536
> ‘libc.so.0.3’ -> ‘libc.so.586asm’
> 30.78     15.69     12.11      9.47      5.63      3.90
> ‘libc.so.0.3’ -> ‘libc.so.1page’
> 28.57     15.54     10.85      8.13      4.39      2.67
> ‘libc.so.0.3’ -> ‘libc.so.2page’
> 29.32     15.30     10.13      8.23      4.51      2.70
> ‘libc.so.0.3’ -> ‘libc.so.3page’
> 29.94     17.07     10.93      8.40      4.55      2.62
> ‘libc.so.0.3’ -> ‘libc.so.4page’
> 28.88     16.64     11.46      8.16      4.39      2.63
> ‘libc.so.0.3’ -> ‘libc.so.inftypage’
> 30.21     14.75     12.33      9.69      6.01      3.91

The effect is more pronounced with pflocal using more memcpy instead
of memmove (bcopy is implemented using memmove).

% bash ~/do_pipebench.bash
Piping 1024 MByte from zero to null.
(dd if=zero bs=X count=overall/X | dd of=null bs=X)
4096      8192     12288     16384     32768     65536
‘libc.so.0.3’ -> ‘libc.so.586asm’
32.57     17.30     12.15      9.38      5.52      3.89
‘libc.so.0.3’ -> ‘libc.so.1page’
29.62     14.26     10.19      7.42      3.43      1.73
‘libc.so.0.3’ -> ‘libc.so.2page’
31.78     14.01      8.69      7.71      3.81      1.81
‘libc.so.0.3’ -> ‘libc.so.3page’
30.90     15.62      8.37      7.12      3.54      1.82
‘libc.so.0.3’ -> ‘libc.so.4page’
31.14     16.40     12.00      7.47      3.81      1.91
‘libc.so.0.3’ -> ‘libc.so.inftypage’
29.83     16.78     11.50      9.50      5.65      3.87

do_pipebench.bash is in the time-memcpy repository.

Justus