ext Raphael Hertzog <hert...@debian.org> writes: > On Wed, 02 Mar 2011, Marius Vollmer wrote: >> - Instead, we move all packages that are to be unpacked into >> half-installed / reinstreq before touching the first one, and put a >> big sync() right before carefully writing /var/lib/dpkg/status. > > The big sync() doesn't work. It means dpkg never finishes its work on > systems with lots of unrelated I/O.
Ok, understood. It's now clear to me that the big sync should be replaced with deferred fsyncs. (I would defer the fsync of the content of all packages until modstatdb_checkpoint, not just until tar_deferred_extract.) With that change, do you think the approach is sound? > We've seen reports of poor performance with btrfs (and that's what you use > for Meego IIRC) so you might want to investigate why btrfs is coping so > badly with a few fsync() just on the status files. This is about Harmattan, which uses ext4. To understand our troubles, you need to know that we have around 2500 packages with just a single file in it. For those packages, dpkg spends the largest part of its time in writing the nine journal entries to /var/lib/dpkg/updates. We will reduce the number of our packages, so this issue might solve itself that way, but I had good success in reducing the per-package overhead of dpkg, and if it is correct and works for us, why not use the 'reckless' option as well? -- To UNSUBSCRIBE, email to debian-devel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/87mxlc8vem....@big.research.nokia.com
