Issue #1527 has been updated by Venkatesh Srinivas. Description updated Assignee changed from 0 to Venkatesh Srinivas
Confirm w/ umass on latest master. Possible leads: 1) msdosfs does not implement runahead/behind support in BMAP, so cluster_read/cluster_write don't get a chance to cluster. FreeBSD has some changes that will help in this regard. 2) NetBSD PR/34583 has a patch to track file-end position, avoiding some chain traversals. Helps w/ write performance on long files. 3) now that device vnodes can implement cluster operations and cluster_awrite is available, msdosfs could set B_CLUSTEROK on metadata writes to devvp. 4) For a more out-there patch, msdosfs could implement double-buffering on writes; the write path would allocate a new buffer, copy data in to it, and mark it as clusterable. The new buffer would be along the device vnode rather than the file vnode. This'll allow all data&metadata to cluster, regardless of file length limits. Would incur copying costs. (This'd be similar to HAMMER's double_buffer mode, except reflected into writes rather than reads). 5) umass may be limiting maximum clustering. This should be investigated -- in my test on master, 4KB writes seemed to be the max. ---------------------------------------- Bug #1527: extremely bad USB/msdos performance http://bugs.dragonflybsd.org/issues/1527 Author: Simon 'corecode' Schubert Status: New Priority: Normal Assignee: Venkatesh Srinivas Category: Target version: The performance for writing to msdosfs on an ehci usb device is pathetic. I'm getting ~500KB/sec, while other OS can do at least 6MB. the rsync process is most of the time in "iowait", "biows", "biord". vmstat: tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id 8 680 60.86 56 3.33 0.00 0 0.00 10.00 2 0.02 3 0 5 0 93 7 400 64.00 2 0.12 0.00 0 0.00 16.00 1 0.02 1 0 5 0 94 10 415 64.00 2 0.12 0.00 0 0.00 0.00 0 0.00 3 0 5 0 92 9 528 0.00 0 0.00 0.00 0 0.00 16.00 2 0.03 2 0 3 0 95 9 541 64.00 4 0.25 0.00 0 0.00 16.00 86 1.34 2 0 6 0 92 10 399 0.00 0 0.00 0.00 0 0.00 16.00 138 2.16 4 0 6 0 90 8 546 64.00 2 0.12 0.00 0 0.00 16.00 4 0.06 7 0 8 0 85 7 509 37.75 89 3.28 0.00 0 0.00 15.68 37 0.57 3 0 8 0 89 10 545 0.00 0 0.00 0.00 0 0.00 16.00 131 2.05 3 0 8 0 89 1 104 4.00 1 0.00 0.00 0 0.00 16.00 40 0.62 5 0 7 0 87 2 226 48.00 86 4.03 0.00 0 0.00 14.29 7 0.10 4 0 6 0 90 102 100 64.00 2 0.12 0.00 0 0.00 16.00 110 1.72 2 0 5 0 93 126 102 64.00 2 0.12 0.00 0 0.00 16.00 37 0.58 3 0 6 0 91 72 103 64.00 1 0.06 0.00 0 0.00 13.29 124 1.61 0 0 4 0 95 42 98 64.00 1 0.06 0.00 0 0.00 0.00 0 0.00 1 0 3 0 96 176 225 45.40 86 3.81 0.00 0 0.00 16.00 2 0.03 4 0 6 0 90 136 104 19.43 84 1.59 0.00 0 0.00 16.00 11 0.17 7 0 8 0 85 70 121 0.00 0 0.00 0.00 0 0.00 16.00 26 0.41 1 0 10 0 89 26 100 64.00 5 0.31 0.00 0 0.00 16.00 140 2.19 2 0 5 0 93 2 219 56.79 91 5.05 0.00 0 0.00 15.79 58 0.89 3 0 6 0 91 -- You have received this notification because you have either subscribed to it, or are involved in it. To change your notification preferences, please click here: http://bugs.dragonflybsd.org/my/account
