Hi, I have tried with a ram disk and ramfs. Read Performance is same as that of disk based system. How did i evaluate? wrote simple program create file on disk,ramfs do pread(...) In fact sometimes the performance is low when using ramdisk or ramfs or dev/shm.
FileSize: 80MB read at once: 20bytes type of read: sequential,meaning in the do loop just increment the offset by 20bytes. Pls guide me how pread can be replaced for ramfs which is much more efficent. Is it possible to avoid this pread system as this consumes significant cpu cycles when it switches from user to kernel mode. regards ragha ****************************************************************************************** This email and its attachments contain confidential information from HUAWEI, which is intended only for the person or entity whose address is listed above. Any use of the information contained herein in any way (including, but not limited to, total or partial disclosure, reproduction, or dissemination) by persons other than the intended recipient(s) is prohibited. If you receive this e-mail in error, please notify the sender by phone or email immediately and delete it! ***************************************************************************************** ----- Original Message ----- From: Rich Shepard <[EMAIL PROTECTED]> Date: Wednesday, August 22, 2007 1:14 am Subject: RE: [sqlite] A Question About Creating and Accessing a SQLite Database in a RAM Drive > On Tue, 21 Aug 2007, Lee Crain wrote: > > > The approach I planned was a little different than what you > proposed. > That's fine, Lee. > > > This technique for performing database updates offline and then > updating> the original database via a file copy operation has > worked very well on > > hard drives. I am only considering using the RAM drive to > improve the > > speed of the database updates. > > This was common in the early 1980s when drives and other > hardware were > slow. I've not seen a situation any time recently when this was > necessarywith modern hardware and fast memory. When I was > capturing real-time data > (lat/lon from the GPS receiver and depth from the sonar), I'd > write both to > memory buffers, then write to disk on a regular basis. This let me use > slower hardware (compared to the data flow) while writing to disk > in chunks > and ensuring that no data were lost. > > I'm confident that you can tune your database for speed in > other ways, but > -- of course -- it's your choice. > > Good luck with it, > > Rich > > -- > Richard B. Shepard, Ph.D. | The Environmental > PermittingApplied Ecosystem Services, Inc. | > Accelerator(TM)<http://www.appl-ecosys.com> Voice: 503-667- > 4517 Fax: 503-667-8863 > > ------------------------------------------------------------------- > ---------- > To unsubscribe, send email to [EMAIL PROTECTED] > ------------------------------------------------------------------- > ---------- > > ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
