Actually, i was curious to see how my old Pentium2 performs, so i tried an ubuntu gutsy on it. Surprising results: root@erebor:~# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 14421344 2177664 11511120 16% / [...] /dev/sda3 273522480 260268272 12230208 96% /local (so one 15gb partition, and one 270gb partition, both ext3) hdparm -tT /dev/sda /dev/sda: Timing cached reads: 158 MB in 2.00 seconds = 78.93 MB/sec Timing buffered disk reads: 84 MB in 3.03 seconds = 27.74 MB/sec crappy results, BUT: root@erebor:~# time cat /local/SAT/aba/bigfile.avi >/dev/null real 0m24.637s user 0m0.236s sys 0m5.676s root@erebor:~# ls -la /local/SAT/aba/bigfile.avi -rw-rw-rw- 1 root root 732903424 2007-05-29 22:43 /local/SAT/aba/bigfile.avi which means about 28mb/sec (what hdparm -t state). Here i still get 0%id cpu, but at least it goes fast. Now: this machine has an intel i440bx chipset. The other one a Via KT600. Both of them run or ran ubuntu gutsy (now the new one has hardy, but before , with gutsy, i had same results) So... is sata_via buggy with via VT8237 soutbridge? On 5/17/08, Paolo <paoletto@xxxxxxxxx> wrote: > Hi Alan, hi all > > so far, i did some more tests. > > First of all, i'm using ext3 filesystem (and it might happen it's very > slow, according with my tests results) > > What i did: > > Trying ubuntu Hardy LiveCD (to check it's not because > 1) im using a hand made compiled kernel > 2) i might have removed some package which is actually needed for disk > performances > 3) the upgrade screwed something ) > > So far, from LiveCD i did the same i did before, that is: > > root@ubuntu:/media/disk/movies# time cat Lo\ squalo.avi >/dev/null > > real 5m16.352s > user 0m0.132s > sys 0m6.244s > root@ubuntu:/media/disk/movies# ls -la Lo\ squalo.avi > -rw-r----- 1 1000 1001 1559521280 2008-03-30 06:37 Lo squalo.avi > > it means roughly those old 5mb/sec. > In the meanwhile i checked with top, and all the cpu cycles were taken > by the disk (about 98.0%wa and 0.0%id) > > ok so not my fault. Maybe ext3? my volumes looks like: > root@rivendell:~# df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/sda1 28834716 17088924 10281068 63% / > [...] > /dev/sda3 931618688 613099244 314519444 67% /local > > So i got a 30gb partition, and a 900gb partition (roughly). > > I tried to copy the file into the smaller partition ( into / ) > and: > > root@rivendell:/# time cp -rf /local/movies/Lo\ squalo.avi / > > real 6m21.978s > user 0m0.150s > sys 0m18.170s > root@rivendell:/# time cat /Lo\ squalo.avi >/dev/null > > real 1m33.913s > user 0m0.150s > sys 0m5.370s > root@rivendell:/# time cat /local/movies/Lo\ squalo.avi >/dev/null > > real 6m13.549s > user 0m0.230s > sys 0m5.930s > > During this tests, the first and the last command still showed like 98.0%wa > while with the second, (reading the file from the / fs) i had about > 50-60%wa and some idle cycles (about 20% or so, sometimes 0% but not > always) with about 16mb/sec transfer rate (which is still slow, to > me.. again, hdparm -tT shows: > root@rivendell:/# hdparm -tT /dev/sda > > /dev/sda: > Timing cached reads: 476 MB in 2.00 seconds = 237.68 MB/sec > Timing buffered disk reads: 220 MB in 3.02 seconds = 72.80 MB/sec ) > > This test shows to me that it might be a filesystem issue, but still, > is it possible it's so expensive? i mean, even from a 30gb partition > (which is the norm) reading operations take almost all the cpu power > (even if it's finally faster). > Ok, my cpu is not lighting fast (AthlonXP 800mhz) but i had almost > better performances on a pentiumII 350mhz and 320gb IDE hard drive > (debian testing on ext3). > > do you have any clue about what could i do to improve fs performances? > Thank you in advance and excuse me for the boring mail! > Paolo > > On 5/1/08, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: >> On Thu, 1 May 2008 21:16:24 +0200 >> Paolo <paoletto@xxxxxxxxx> wrote: >> >>> Umh.. >>> >>> Thank you for your answer! >>> Actually, i think the same. Hdparm tests shows good results. >> >> hdparm results mean the disk setup is ok >> >>> what i dont get is why the cpu load raise to keep idle to 0% like if >>> it was pio mode, even if it is in udma6.. >>> What else could be, other than the libata layer not setted in dma >>> (which is not)? >> >> Anything above the disk driver layer - file system, block queue setup >> or something happening which causes a lot of I/O in small chunks (which >> ruins a disks performance). This is usually distro level stuff so best >> analysed by the distribution people. >> >>> ps: no, im not using LVM. But ubuntu is using their uuid stuff in >>> fstab to boot which i quite dont know at all.. >>> maybe that? >> >> No that wouldn't explain it at all. The uuid/fstab stuff is just boot >> time stuff so doesn't get in the way. >> >> What file system are you using ? >> > -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
