On Sat, Mar 14, 2009 at 2:55 PM, Vineet Agarwal <checkout.vineet@xxxxxxxxx> wrote: > hello Greg, > > sorry i didn't followed it right > > Now it's done. this is the output.. > > [root@fscops Memcopy]# time (cp /test_256.db /mnt; sync) > real 0m24.039s > user 0m0.022s > sys 0m1.566s > Hmmm, still almost twice as fast. I assume the old time for the kernel module is still valid. ie. Adding the 2 calls to sync and the drop_caches logic did not make much difference. >> time insmod mmcpy.ko inum=12 (without sync_dirty_buffers) real 0m47.679s user 0m0.002s sys 0m12.838s >> The 12 seconds of system time is very surprising. Please remind me, how much data (in bytes) are you reading / writing per iteration? If it is not a multiple of 4K it can cause big inefficiencies. ie. The linux kernel uses a 4K page size and you want to try to use a multiple of that for all i/o calls or things go bad from a performance perspective. Greg -- Greg Freemyer Head of EDD Tape Extraction and Processing team Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
