Re^7: Working with fixed length files (Crap benchmark!)

The reason all the code runs the same speed is because sysread doesn't work on ramfiles, so the loops are never being entered.

That also explains the dramatic slowdown affect of local $/ = \nnn;. It adds an operation to a call that does almost nothing, and twice almost nothing is longer than 1 times almost nothing.

Which brings up another mystery entitled: "The Strange Case of the Disappearing AutoDie".

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

Comment on Re^7: Working with fixed length files (Crap benchmark!) Download Code

Replies are listed 'Best First'.
Re^8: Working with fixed length files (Crap benchmark!) by Tux (Canon) on Apr 29, 2011 at 09:46 UTC
`autodie` was removed so I could bench on older perls. Good analisys! That should teach me :/ `sysread` basically means "bypass PerlIO, do a `read ()`", so that means PerlIO::scalar doesn't get a say in it. However whether that is how things should be is a different matter. Enjoy, Have FUN! H.Merijn	[reply] [d/l] [select]
Re^8: Working with fixed length files (Crap benchmark!) by Tux (Canon) on Apr 29, 2011 at 11:37 UTC
With all `sysread`'s re-placed by `read`'s my bench shows much more reliable figures: `Rate buk ike1 ike2 buk 81.1/s -- -43% -46% ike1 143/s 76% -- -5% ike2 150/s 85% 5% --` [download] I think it would be hard to reduce the overhead even more. Read more... (3 kB) Enjoy, Have FUN! H.Merijn	[reply] [d/l] [select]