On 07/10/2012 11:22 PM, Eric Haszlakiewicz wrote: > On Tue, Jul 10, 2012 at 09:09:29PM +0200, Lars Heidieker wrote: >> slight improvement on kmem(9): >> >> splitting the lookup table into two parts >> - this reduces the size of the lookup table -> touching less cache-lines >> (e.g. on 64bit down from 4096b to 1024b + 64b) >> - expanding cache size up to PAGE_SIZE for larger then 4k PAGE_SIZE >> machines (without blowing up the size of the lookup table further) >> >> The size check under DIAGNOSTIC is moved back to the start of the >> allocated as it makes it more useful and we have given up the PAGE_SIZE >> alignment for kmem(9) on allocations >= PAGE_SIZE. >> >> any objections? > > Have you done any performance tests? How much of a difference does this make? > > eric >
Some testing shows that system time goes down slightly (taken from full release build on 4-core) modififed 1478.03 1420.89 stock 1486.48 1436.89 the two runs are not comparable different checkout all source pull to fs cache before run So not statistically proven a slight win and better suited for PAGE_SIZE > 4k Lars -- ------------------------------------ Mystische Erklärungen: Die mystischen Erklärungen gelten für tief; die Wahrheit ist, dass sie noch nicht einmal oberflächlich sind. -- Friedrich Nietzsche [ Die Fröhliche Wissenschaft Buch 3, 126 ]
