On Fri, Oct 1, 2010 at 11:51 PM, Alan Altmark <[email protected]> wrote:
> According to documents on the web, timestamps are part of the PREFIX and > DEFINE EXTENT CCWs. However, you will not find any documentation of > PREFIX, nor of the extensions to DEFINE EXTENT (no pun intended). Another > case of RTFC, as LINUX will use them. > > I think you need to move your tracing out of the realm of CCWs and > consider whether Linux can trace the timestamps it is using in its I/O. Browsing a few Linux source files suggests that you should be able to recognize it by the data length in your Define Extent CCW. We used to do 16 byte, from what dasd_eckd.h tells me XRC adds another 16 (and uses some of the reserved bytes). An I/O trace with CCW option should reveal it... And since someone asked that a while ago; once RDC shows the device can, Linux appears to include the time stamps. | Rob
