Date: Fri, 5 Oct 2007 04:48:20 +0400 From: Dmitry Marakasov <amdmi3@amdmi3.ru> To: freebsd-fs@freebsd.org Subject: Very slow writes on flash + msdosfs Message-ID: <20071005004820.GA29814@hades.panopticon>
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Hi! I have USB flash: da0 at umass-sim0 bus 0 target 0 lun 0 da0: <JetFlash TS2GJF150 8.07> Removable Direct Access SCSI-2 device da0: 40.000MB/s transfers da0: 1999MB (4095998 512 byte sectors: 255H 63S/T 254C) It attaches to ehci and I get pretty good read/write speed: % dd if=/dev/zero of=/dev/da0 bs=1m dd: /dev/da0: short write on character device dd: /dev/da0: end of device 2000+0 records in 1999+1 records out 2097150976 bytes transferred in 178.132363 secs (11772993 bytes/sec) % dd if=/dev/da0 of=/dev/zero bs=1m count=100 100+0 records in 100+0 records out 104857600 bytes transferred in 7.240738 secs (14481618 bytes/sec) But newfs_msdos ran on it is very slow: % time newfs_msdos -F32 -LAMDmi3 -k 0xffff /dev/da0s1 /dev/da0s1: 4072456 sectors in 509057 FAT32 clusters (4096 bytes/cluster) bps=512 spc=8 res=32 nft=2 mid=0xf0 spt=63 hds=255 hid=0 bsec=4080447 bspf=3978 rdcl=2 infs=1 bkbs=0xffff newfs_msdos -F32 -LAMDmi3 -k 0xffff /dev/da0s1 0,02s user 0,21s system 0% cpu 2:54,37 total when it runs, gkrellm shows 23kb/s writes. Writing a 1.0Mb directory with 340 files takes 1.5 minutes (up to 300k/sec writes => seems like much more data is actually written that it's needed). Larger files behave somewhat better (up to 3 MB/s). Btw, dd if=/dev/zero of=/dev/da0 bs=512 show the same 23k/s speed as newfs_msdosfs. So where is the problem? Why's there no caching and why's there 1 sector writes? PS. I use 6.1, has the situation changed in -CURRENT? -- Best regards, Dmitry Marakasov mailto:amdmi3@amdmi3.ru
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