On Fri Jan 28, 2011 at 03:18:38AM -0000, Dustin Kirkland <[email protected]> wrote: > time dd if=/dev/zero of=~/dummy bs=512 count=10240
There are a couple issues here: 1. eCryptfs currently implements a write-through cache. This means that reads are cached, but writes are not. There's currently someone investigating a switch to a proper write-back cache on files opened without the O_SYNC flag. This would result in writes being cached and, more importantly, write() returning before the page is encrypted. Some rough, initial tests show a very nice improvement. 2. bs=512 results in a 4 writes to a single page, meaning that single page is encrypted 4 times in a row and dd has to wait on the page encryption and writing 4096 bytes to the lower filesystem every time. This is why doing what I talked about in #1 has so much potential to increase performance. Encryption isn't free, but we should be a little smarter about when we do it. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/654764 Title: writing to ecryptfs partition on SSD drive is many times slower than writing to unencrypted partition on the same drive -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
