On Thu, Jan 22, 2009 at 3:49 AM, Sandeep K Sinha <sandeepksinha@xxxxxxxxx> wrote: > > Help us with the benchmarking ? My first question would be: Why are you benchmarking at all? I can see a basic benchmark just to prove you are actually moving data in a reasonably efficient way. Disk drives are notoriously slow, so once you hit 100% of max throughput a simple benchmark is rather pointless. Unless you are tuning your block allocation code to try and create defrag-ed files. I assume that functionality is down the road. SSDs may be faster the HDD, but to go really fast you will need to have both the original tier and the destination tier on SSD. (You can just partition one in half I assume.) But the only production SSD that is fast to randomly write that I am aware of is the Intel line. Is that what you are testing with? If not, do you believe your destination blocks are defragged? Come to think of it, I don't even know what defrag means on a SSD? Given there is a mapping layer, how would one even try to do it? Anyway the most important benchmark would be to simply assure you are maxing out the theoretical max of the storage devices you are testing with. Have you done that yet? FYI: A simple userspace dd can effectively do that in most cases. So that gives you a quick and dirty reference. If you are not at least as fast as userspace, you have broken code. if you are 2x faster than user space, I would be very suspicious you also have broken code. Or at least a broken benchmark. To me once you get that basic benchmark achieved, functional testing would a much higher priority than benchmarking. Greg -- Greg Freemyer 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
