On 01.06.2016 16:12, Theodore Ts'o wrote: > On Wed, Jun 01, 2016 at 03:17:14PM +0200, Gernot Hillier wrote: >> I repeated the discussed tests and found comparable results on this machine: >> >> - 3 seconds dpkg install time on ext3 vs. 80 seconds for ext4 >> on same partition for same package >> - 40 ms for fallocate+write+sync_file_range for writing a few bytes >> - 15 ms for write+fdatasync vs. 45 ms for BLKZEROOUT on raw device >> >> So this seems to be not bound to one specific disk+controller setup, but >> it still can't be a common problem affecting many people as then we >> would see more reports about it... > > OK, so let's try to get common baseline, shall we? Sure! > I'm using as my test package: > > http://debug.mirrors.debian.org/debian-debug/pool/main/e/e2fsprogs/e2fsprogs-dbgsym_1.43-3_amd64.deb [...] > # /usr/bin/time dpkg --force-depends -i /tmp/e2fsprogs-dbgsym_1.43-3_amd64.deb [...] > 0.21user 0.19system 0:00.54elapsed 74%CPU (0avgtext+0avgdata 73188maxresident)k > 0inputs+10168outputs (0major+24935minor)pagefaults 0swaps On machine with Intel SCSI controller and on ext4 root, I see: 0.15user 0.00system 0:00.92elapsed 16%CPU (0avgtext+0avgdata 14144maxresident)k 0inputs+0outputs (0major+5447minor)pagefaults 0swaps Installing to some ext3 partition: 0.14user 0.01system 0:00.56elapsed 26%CPU (0avgtext+0avgdata 14092maxresident)k 0inputs+0outputs (0major+5431minor)pagefaults 0swaps This doesn't really advertise the issue as it only installs a small number of files - yet, I still see a reproducible factor of 1.5-2 for total elapsed time between ext3 and ext4... > Something else would be useful is to make sure /tmp is a tmpfs mounted > file system (so you don't get any I/O's caused by /tmp), and then do: Ok. > # dpkg --purge e2fsprogs-dbgsym > # btrace /dev/sda3 > /tmp/btrace.out & > # /usr/bin/time dpkg --force-depends -i /tmp/e2fsprogs-dbgsym_1.43-3_amd64.deb > # kill %btrace Please find btrace.out.bz2 attached. HTH... Please note that I'm offline for the next couple of days, so there will be some delay in my answers! -- Gernot Hillier Siemens AG, Corporate Technology Corporate Competence Center Embedded Linux
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