Hello On Thu, 2006-06-08 at 13:35 +0200, Jens Axboe wrote: > On Thu, Jun 08 2006, Vladimir V. Saveliev wrote: > > Hello > > > > On Thu, 2006-06-08 at 13:00 +0200, Jens Axboe wrote: > > > On Wed, May 24 2006, Hans Reiser wrote: > > > > Tom Vier wrote: > > > > > > > > >On Tue, May 23, 2006 at 01:14:54PM -0700, Hans Reiser wrote: > > > > > > > > > > > > > > >>underlying FS can be improved. Performance results show that the new > > > > >>code consumes 40% less CPU when doing "dd bs=1MB ....." (your > > > > >>hardware, > > > > >>and whether the data is in cache, may vary this result). Note that > > > > >>this > > > > >>has only a small effect on elapsed time for most hardware. > > > > >> > > > > >> > > > > > > > > > >Write requests in linux are restricted to one page? > > > > > > > > > > > > > > > > > > > It may go to the kernel as a 64MB write, but VFS sends it to the FS as > > > > 64MB/4k separate 4k writes. > > > > > > Nonsense, > > > > Hans refers to generic_file_write which does > > prepare_write > > copy_from_user > > commit_write > > for each page. > > Provide your own f_op->write() ? > Yes, a filesystem can do that. But it is more welcomed to kernel if it writes/reads using generic functions.
> > > there are ways to get > PAGE_CACHE_SIZE writes in one chunk. > > > Other file systems have been doing it for years. > > > > > > > Would you, please, say more about it. > > Use writepages? > This is about flushing, not sys_write.
