From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: 2.6.16-rc6-mm2: slow writes on reiser4. Date: Tue, 21 Mar 2006 23:41:22 -0800 Message-ID: <4420FFA2.1090908@namesys.com> References: <44206D3C.7050504@free.fr> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <44206D3C.7050504@free.fr> List-Id: Content-Type: text/plain; charset="iso-8859-1" To: Laurent Riffard Cc: reiserfs-list@namesys.com, vs , Alexander Zarochentcev Laurent Riffard wrote: >Hello, > >Writing big files is very slow on reiser4 now.=20 > >"dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; sync" > try bs=3D4M, and tell me what happens. also try an empty fs, and an fs that is equally full to reiserfs. Note that reiserfs in your test is 68% full vs. 90% full for V4. It may be that we need to port some of the block allocation optimizations from V3 to V4 (Jeff's work) to help with 90% full filesystems. Thanks for doing this. Real users always teach me a lot when they test things differently from how I did. Hans > takes more than 2 minutes on=20 >reiser4 fs, but only 15 seconds on reiserfs fs. > >Actually, writing on reiser4 is not uniformly slow, it seems to be blocked= for=20 >ages from time to time. I monitored the number of dirty pages from /proc/m= eminfo=20 >an I hit sysrq-T when the system was stalling: =20 > >dd D 000017DE 0 21930 21929 (NOTLB) > d7169c74 e0c98b05 00000246 000017de 00000000 f396aa00 003d1249 d0b6= 8140 > d0b68030 f396aa00 003d1249 6d519e00 00000002 c0396434 d8bf8e30 d8bf= 8e38 > 00000246 d7169ca0 c0270f08 d0b68030 00000001 d0b68030 c0113b25 d8bf= 8e38 >Call Trace: > [] __down+0x81/0xdc > [] __down_failed+0xa/0x10 > [] .text.lock.lock+0x15/0x1b [reiser4] > [] longterm_lock_znode+0x5b4/0x7b0 [reiser4] > [] cbk_level_lookup+0x8a/0x954 [reiser4] > [] traverse_tree+0x752/0xa0d [reiser4] > [] coord_by_handle+0x781/0x789 [reiser4] > [] object_lookup+0x1eb/0x230 [reiser4] > [] find_file_item+0x18d/0x1b7 [reiser4] > [] write_flow+0x208/0x6e1 [reiser4] > [] write_unix_file+0x3d9/0x5b0 [reiser4] > [] vfs_write+0x8a/0x133 > [] sys_write+0x3b/0x60 > [] sysenter_past_esp+0x54/0x75 > >Below are the detailed test I ran. Feel free to ask for more information. > >Reiser4 FS >=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > >Desktop$ cd ~/kernel > >kernel$ df . >Sys. de fich. Tail. Occ. Disp. %Occ. Mont=E9 sur >/dev/hda8 925M 825M 101M 90% /home/laurent/kernel > >kernel$ grep hda8 /proc/mounts >/dev/hda8 /home/laurent/kernel reiser4 rw,nosuid,nodev,atom_max_size=3D0x7= e0c,atom_max_age=3D0x249f0,atom_min_size=3D0x100,atom_max_flushers=3D0x1,cb= k_cache_slots=3D0x10 0 0 > >kernel$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; tim= e sync=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.06user 13.95system 1:42.09elapsed 13%CPU (0avgtext+0avgdata 0maxresident= )k >0inputs+0outputs (0major+250minor)pagefaults 0swaps >0.00user 0.00system 1:22.90elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+191minor)pagefaults 0swaps > >kernel$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; tim= e sync=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.08user 14.01system 1:45.57elapsed 13%CPU (0avgtext+0avgdata 0maxresident= )k >0inputs+0outputs (0major+249minor)pagefaults 0swaps >0.00user 0.00system 0:09.78elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+191minor)pagefaults 0swaps > >kernel$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; tim= e sync=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.06user 14.13system 2:18.27elapsed 10%CPU (0avgtext+0avgdata 0maxresident= )k >0inputs+0outputs (0major+251minor)pagefaults 0swaps >0.00user 0.00system 0:08.48elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+190minor)pagefaults 0swaps > >kernel$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; tim= e sync=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.06user 14.27system 1:56.34elapsed 12%CPU (0avgtext+0avgdata 0maxresident= )k >0inputs+0outputs (0major+251minor)pagefaults 0swaps >0.00user 0.00system 0:10.46elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+190minor)pagefaults 0swaps > > >Reiserfs FS >=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >kernel$ cd > >~$ df . >Sys. de fich. Tail. Occ. Disp. %Occ. Mont=E9 sur >/dev/mapper/vglinux1-lvhome > 7,0G 4,8G 2,3G 68% /home >[/dev/mapper/vglinux1-lvhome resides on /dev/hda4] > >~$ grep lvhome /proc/mounts >/dev/vglinux1/lvhome /home reiserfs rw 0 0 > >~$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; time syn= c=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.04user 1.75system 0:02.05elapsed 87%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+249minor)pagefaults 0swaps >0.00user 0.10system 0:12.93elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+191minor)pagefaults 0swaps > >~$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; time syn= c=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.04user 1.83system 0:01.98elapsed 94%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+250minor)pagefaults 0swaps >0.00user 0.16system 0:14.45elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+191minor)pagefaults 0swaps > >~$ sync; time dd if=3D/dev/zero of=3Dtoto bs=3D1k count=3D102400; time syn= c=20 >102400+0 enregistrements lus. >102400+0 enregistrements =E9crits. >0.04user 1.79system 0:01.95elapsed 93%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+250minor)pagefaults 0swaps >0.00user 0.10system 0:13.47elapsed 0%CPU (0avgtext+0avgdata 0maxresident)k >0inputs+0outputs (0major+190minor)pagefaults 0swaps > >~~ >laurent > > > =20 >