An Unencrypted Look at FileVault
Subject:   FileVault performance tax
Date:   2008-07-21 15:50:00
From:   softweyr
Response to: FileVault performance tax

I know this is age-old, but I want to reply just in case somebody else trips across this drivel. The Linux kernel guys long ago decided to "micro-optimize" certain trivial Linux system calls, including getpid(), so getpid() is no longer useful as a kernel micro benchmark on Linux. The first time you call getpid(), it does the syscall and retrieves the actual pid, every time after this it uses a cached copy of the pid. This makes getpid() useless as a microbenchmark to compare Linux to any other system, and was a waste of time for real applications which are unliked to spin on getpid(), but an indication of the Linux mindset in optimizing silly things that don't matter.