On Tue, Oct 18, 2011 at 12:53 AM, Florian Philipp <li...@binarywings.net> wrote: > Am 18.10.2011 07:16, schrieb Paul Hartman: >> On Wed, Oct 12, 2011 at 8:52 PM, Pandu Poluan <pa...@poluan.info> wrote: >>> Just stumbled upon this blog: >>> >>> http://www.webupd8.org/2011/10/increased-performance-in-linux-with.html >>> >>> anyone got any experience with zram/compcache on Gentoo? >> >> I'm using zram in a gentoo server with only 256mb of RAM, only used >> for a few weeks so far. It seems to work and the server hasn't crashed >> yet. :) I have allocated 128MB of compressed swap (64x2, actually, to >> theoretically utilize both CPU cores for compression at the same time) >> followed by normal on-disk swap at lower priority. Usually my total >> swap used is less than 128MB so the real disk swap is rarely touched. >> It's difficult to say if there is any improved performance, but I >> haven't experienced any slowdown, which occasionally I did when swap >> became heavily used in the past. Keep in mind the 128MB zram is the >> uncompressed size, so the actual amount of RAM used by this should be >> much less, depending on contents of the swap. Some even recommend >> using zram equal to the amount of RAM but that idea scares me. >> >> After enabling the CONFIG_ZRAM module in kernel 3.0.6, I did this: >> >> modprobe zram num_devices=2 >> echo $((64*1024*1024)) > /sys/block/zram0/disksize >> echo 1 > /sys/block/zram0/reset > # sleep 1 >> mkswap /dev/zram0 >> swapon -p 11 /dev/zram0 >> > > In my experience, it can be necessary to put a `sleep 1` between reset > and mkswap because the /dev/zram0 disappears and reappears after the > reset command.
Good to know, thanks. In my case I typed those commands manually, so of course I didn't encounter any timing-related problem like that. > Another remark: The kernel docs recommend using /bin/echo instead of > echo because problems are reported as write errors and the echo builtin > of bash doesn't check for that. Also noted, thanks again.
