Hi Martin, At the first glance, I find ureadahead has some difference compared with the readahead once in systemd, IIRC:
1. ureadahead.service is in default.target, which means ureadahead starts later than systemd's? 2. The original systemd readahead has "collect" and "replay" two services, and these are done in ureadahead.service? 3. IIRC, The original systemd readahead uses madvise(); ureadahead uses readahead() 4. The original systemd readahead uses fanotify() to get the list of accessed files; ureadahead use fsnotify 5. ureadahead has different readahead strategies for ssd and hhd: 5.1 For the former, initiate multi-threads to perform readahead, and they are running at the lowest IO priority. 5.2 For the later, perform readahead for both inode and file content at a very high CPU/IO priority (and only support extN filesystem ?) 2015-05-18 18:40 GMT+08:00 Martin Pitt <martin.p...@ubuntu.com>: > Hello cee1, > > cee1 [2015-05-18 18:24 +0800]: >> Does the readahead-*.service shipped with systemd work for you? > > systemd dropped the builtin readahead in 217. It's reasonably easy to > get back by reverting the "drop readahead" patches, but carrying that > patch in packages is fairly intrusive. In Ubuntu we've had > "ureadahead" [1] for many years which is "good enough" for things like > phones or other ARM boards with slow MMC storage, so I just added > systemd units to that. It's a separate project so that we don't need > to install ureadahead everywhere, just where/when we actually need it. > > Martin > > [1] https://launchpad.net/ubuntu/+source/ureadahead > -- > Martin Pitt | http://www.piware.de > Ubuntu Developer (www.ubuntu.com) | Debian Developer (www.debian.org) -- Regards, - cee1 _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
