Re: scsi vs ide performance on fsync's

Steve Lord
2001-03-02T19:41:39Z

>
>
> On Friday, March 02, 2001 01:25:25 PM -0600 Steve Lord <lord@sgi.com> wrote:
>
> >> For why ide is beating scsi in this benchmark...make sure tagged queueing
> >> is on (or increase the queue length?). For the xlog.c test posted, I
> >> would expect scsi to get faster than ide as the size of the write
> >> increases.
> >
> > I think the issue is the call being used now is going to get slower the
> > larger the device is, just from the point of view of how many buffers it
> > has to scan.
>
> filemap_fdatawait, filemap_fdatasync, and fsync_inode_buffers all restrict
> their scans to a list of dirty buffers for that specific file. Only
> file_fsync goes through all the dirty buffers on the device, and the ext2
> fsync path never calls file_fsync.
>
> Or am I missing something?
>
> -chris
>
>

No you are not, I will now go put on the brown paper bag.....

The scsi thing is wierd though, we have seen it here too.

Steve