Hi Steve, On Thu, 26 Sep 2013 12:22:49 -0500 Steve French <smfrench@xxxxxxxxx> wrote: > Windows clients seem to max out at 16MB chunk size when doing copy > offload. I would like to increase chunk size larger than that if > network bandwidth (returned at mount time in SMB3 on the query network > interfaces FSCTL) is large enough, and response time is not more than > 100 (?) milliseconds. Sounds good, though with Samba and Btrfs the request latency will be heavily effected by whether the FSCTL_SRV_COPYCHUNK wire request byte offsets and lengths align to the Btrfs sector-size (4K by default IIRC). If they do align, then each chunk in the request can be mapped to a BTRFS_IOC_CLONE_RANGE ioctl. Otherwise, we need to fall back to a server-side local read/write. We should be able to provide underlying filesystem alignment requirements to SMB clients via the new FileFSSectorSizeInformation ioctl, but it's not currently supported by Samba. Cheers, David -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
