On Fri, Sep 13, 2013 at 5:54 PM, Ben Widawsky <ben@xxxxxxxxxxxx> wrote: > On Fri, Sep 13, 2013 at 11:12:11AM +0200, Daniel Vetter wrote: >> On Thu, Sep 12, 2013 at 10:28:41PM -0700, Ben Widawsky wrote: >> > Haswell added the ability to inject errors which is extremely useful for >> > testing. Add two arguments to the tool to inject, and uninject. >> > >> > Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx> >> >> Do we run any risk that a concurrent write/read to the same register range >> could hang the machine due to the same-cacheline w/a we need? Just want to >> make sure that when we integrate this into a testcase there's no surprises >> like with intel_gpu_top ... >> -Daniel > > The race against the kernel is ever present on all tests/tools. Are we > running parallel igt yet? If so, I can make the read/write functions > threadsafe. > > On this note in particular I suppose we can make a debugfs entry like > the forcewake one to allow user space to do register accesses. > > Interestingly, this also reminds me of another caveat I meant to put in > the commit message and forgot... the error injection register is also > per context, which makes it a pain to clear (and the pain in writing the > test case). I'm even beginning to think maybe a debugfs for this > register is the way to go. > > As a side note, the injection feature is entirely debug only - but > agreed, random hangs in the test suite is not good. Hm, this will be tricky. If nothing else writes this range (i.e. not our interrupt handler) we could use a secure batchbuffer and emit the MI_LRI from the userspace batch. Then we could submit some workload using hw contexts that uses the l3$ cache (I guess without something in there it won't notice the injected error) and after the error is detected we could simply kill the context, restoring the original state again. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
