<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [bsw] execlists causes machine lockups" href="https://bugs.freedesktop.org/show_bug.cgi?id=93467#c13">Comment # 13</a> on <a class="bz_bug_link bz_status_ASSIGNED " title="ASSIGNED - [bsw] execlists causes machine lockups" href="https://bugs.freedesktop.org/show_bug.cgi?id=93467">bug 93467</a> from <a class="email" href="mailto:tvrtko.ursulin@linux.intel.com" title="Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>"> Tvrtko Ursulin</a> <pre>On my BDW I need a kernel with no debugging whatsoever to trigger this reliably. No tracing, no lockdep, even basic spinlock debugging needs to be turned off. In that setup gem_exec_nop/basic generates ~340k interrupts per second and creates numerous 10-20 second system-wide stalls. I've tried to measure the durations of various sections of the code in intel_lrc.c, and although the averages and maximums are bad (if my numbers are correct we can spend 10-25% of elapsed test time with interrupts off), I can't find anything which would block for 10-20 seconds in one go. And by inspecting the code I also can't figure out how it would happen. Also, these lockups in general seem to come and go in batches. Sometimes the system is happily chugging along with 340k irq/s, and sometimes it is stalling all the time. What makes it latch to one of these modes I have no idea. At one point I thought I see a correlation with the retire worker, but then it went away. It still feels upgrading the trylock there with a real lock improves things (more short lockups vs long ones), but I can't figure out why that would make sense.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> </ul> </body> </html>