On Thu, Jul 15, 2010 at 3:56 PM, Carlos Alvarez <cbalva...@gmail.com> wrote: > On Thu, Jul 15, 2010 at 2:01 PM, Jonathan Ellis <jbel...@gmail.com> wrote: >> The main problem is not the syscall so much as Java insisting on >> zeroing out any buffer you create, which is a big hit to performance >> when you're allocating buffers for file i/o on each request instead of >> just mmaping things. Re-using those buffers would be possible but >> difficult; I think using mlockall to "fix" the mmap approach is more >> promising. > > Sorry if it is a silly question, but what would be the approach? issue > a mlockall with the current set (MLC_CURRENT) before mmap the files?
right > Did someone have an opinion on that > http://delivery.acm.org/10.1145/1820000/1814327/p20-kamp.pdf?key1=1814327&key2=0207229721&coll=GUIDE&dl=GUIDE&CFID=97156491&CFTOKEN=66732025 > ?. > > Do you think it could be useful for cassandra to arrange things in the > files in order to try to have that kind of 'page afinity' in the data > and minimize the page faults trasversing the data? that's exactly what the sstable index design is already doing -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com
