Messages in this thread | | | Date | Fri, 02 Mar 2001 12:39:01 -0600 | From | Steve Lord <> |
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> > > We're doing some mysql benchmarking. For some reason it seems that ide > drives are currently beating a scsi raid array and it seems to be related > to fsync's. Bonnie stats show the scsi array to blow away ide as > expected, but mysql tests still have the idea beating on plain insert > speeds. Can anyone explain how this is possible, or perhaps explain how > our testing may be flawed? >
The fsync system call does this:
down(&inode->i_sem); filemap_fdatasync(inode->i_mapping); err = file->f_op->fsync(file, dentry, 0); filemap_fdatawait(inode->i_mapping); up(&inode->i_sem);
the f_op->fsync part of this calls file_fsync() which does:
sync_buffers(dev, 1);
So it looks like fsync is going to cost more for bigger devices. Given the O_SYNC changes Stephen Tweedie did, couldnt fsync look more like this:
down(&inode->i_sem); filemap_fdatasync(ip->i_mapping); fsync_inode_buffers(ip); filemap_fdatawait(ip->i_mapping); up(&inode->i_sem);
Steve Lord
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