When I use my GPLPV drivers with tap:aio, I get a random BSoD after a while, normally 0x0000000A. Can anyone suggest what could be different with file|phy vs tap:aio that might cause a problem? Is tap:aio otherwise known to be good? Thanks James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> > When I use my GPLPV drivers with tap:aio, I get a random BSoD after a > while, normally 0x0000000A. > > Can anyone suggest what could be different with file|phy vs tap:aiothat> might cause a problem? Is tap:aio otherwise known to be good? >Forgot to add, the underlying file is sparse. Thanks James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
James Harper wrote:> When I use my GPLPV drivers with tap:aio, I get a random BSoD after a > while, normally 0x0000000A. > > Can anyone suggest what could be different with file|phy vs tap:aio that > might cause a problem? Is tap:aio otherwise known to be good? >I guess the main difference is likely to be blkback vs. blktap. Guessing from the minimal info., I''m guessing you''re probably hitting a state model problem. Was there any significant PnP going on when you got the BSOD? Paul -- ==============================Paul Durrant, Software Engineer Citrix Systems (R&D) Ltd. ============================== _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> > James Harper wrote: > > When I use my GPLPV drivers with tap:aio, I get a random BSoD aftera> > while, normally 0x0000000A. > > > > Can anyone suggest what could be different with file|phy vs tap:aiothat> > might cause a problem? Is tap:aio otherwise known to be good? > > > > I guess the main difference is likely to be blkback vs. blktap.Guessing> from the minimal info., I''m guessing you''re probably hitting a state > model problem. Was there any significant PnP going on when you got theBSOD?>No PnP. I/O was being saturated though - I was performing a restore via network to the disk on the machine that crashed. Using phy: or file: I can restore 600GB with no problems at all. With tap:aio it crashes after a few tens of GB. James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
James Harper wrote:> > No PnP. I/O was being saturated though - I was performing a restore via > network to the disk on the machine that crashed. > > Using phy: or file: I can restore 600GB with no problems at all. With > tap:aio it crashes after a few tens of GB. >Another guess then... tap will probably have more outstanding transactions than back as its datapath is likely to be longer and so is higher latency. Is your frontend overflowing a queue of outstanding SRBs? Paul -- ==============================Paul Durrant, Software Engineer Citrix Systems (R&D) Ltd. First Floor, Building 101 Cambridge Science Park Milton Road Cambridge CB4 0FY United Kingdom TEL: x35957 (+44 1223 225957) ============================== _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> > James Harper wrote: > > > > No PnP. I/O was being saturated though - I was performing a restorevia> > network to the disk on the machine that crashed. > > > > Using phy: or file: I can restore 600GB with no problems at all.With> > tap:aio it crashes after a few tens of GB. > > > > Another guess then... tap will probably have more outstanding > transactions than back as its datapath is likely to be longer and sois> higher latency. Is your frontend overflowing a queue of outstandingSRBs?>Thanks, that''s a good lead. I think Windows is pretty limiting in the amount of outstanding I/O that it allows (16 outstanding requests?) but maybe that is too much for tap... I''ll double check that I am catering for a ring-full condition. James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel