On Wed, Nov 19, 2014 at 4:07 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > On Tue, Nov 18, 2014 at 11:19 PM, Michel Dänzer <michel@xxxxxxxxxxx> wrote: >> On 19.11.2014 09:21, Andy Lutomirski wrote: >>> >>> On Mon, Nov 17, 2014 at 1:51 AM, Michel Dänzer <michel@xxxxxxxxxxx> wrote: >>>> >>>> On 15.11.2014 07:21, Andy Lutomirski wrote: >>>>> >>>>> >>>>> On recent kernels (3.16 through 3.18-rc4, perhaps), doing anything >>>>> graphics intensive seems to cause my system to become unusable for >>>>> tens of seconds. Pointing Firefox at Google Maps is a big offender -- >>>>> it can take several minutes for me to move my mouse far enough to >>>>> close the tab and get my computer back. >>>>> >>>>> On bootup, I get this warning: >>>>> [drm:btc_dpm_set_power_state] *ERROR* >>>>> rv770_restrict_performance_levels_before_switch failed >>>>> >>>>> Setting radeon.dpm=0 seems to work around this problem at the cost of >>>>> giving my rather slow graphics. >>>>> >>>>> Are there known issues here? >>>> >>>> >>>> >>>> Can you bisect the kernel, or at least isolate which kernel version first >>>> introduced the problem? >>> >>> >>> With whatever userspace I'm running, I'm seeing it 3.13, 3.14, 3.15, >>> 3.16, and 3.18-rc4+. I haven't tried other versions. >>> >>> With radeon.dpm=0, I can still trigger short stalls (around one >>> second), but I seem unable to trigger long stalls easily. (I say >>> easily because, just as I was typing this email, my system stalled for >>> about a minute.) >> >> >> I can only think of two things offhand that could cause such extremely long >> stalls: Swap thrashing or IRQ storms. >> >> With a setup where you can easily trigger long stalls, can you try getting a >> CPU profile for a stall with sysprof or perf? >> >> > > Got one with perf: > > 16.82% Xorg libc-2.18.so [.] > __memcpy_sse2_unaligned > 9.20% swapper [kernel.kallsyms] [k] intel_idle > 1.00% Xorg [kernel.kallsyms] [k] > evergreen_irq_set > 0.83% firefox libxul.so [.] > 0x0000000001d93281 > 0.69% firefox libxul.so [.] > 0x0000000001d932ad > 0.62% firefox [kernel.kallsyms] [k] > copy_user_generic_string > 0.55% swapper [kernel.kallsyms] [k] > evergreen_irq_ack > 0.54% firefox libpthread-2.18.so [.] > pthread_mutex_lock > 0.52% firefox libpthread-2.18.so [.] > pthread_mutex_unlock > 0.45% Xorg [kernel.kallsyms] [k] > drm_mm_insert_node_in_range_generic > 0.41% Xorg [kernel.kallsyms] [k] lock_release > 0.40% Xorg [kernel.kallsyms] [k] lock_acquire > 0.35% firefox firefox [.] > 0x000000000001245d > 0.33% Xorg [kernel.kallsyms] [k] > __module_address > 0.31% firefox [kernel.kallsyms] [k] clear_page_c > 0.29% Xorg [kernel.kallsyms] [k] > copy_user_generic_string > 0.28% firefox firefox [.] > 0x0000000000013159 > > and: > > Samples: 11K of event 'irq:irq_handler_entry', Event count (approx.): 11802 > 87.43% swapper [kernel.kallsyms] [k] handle_irq_event_percpu > 7.52% firefox [kernel.kallsyms] [k] handle_irq_event_percpu > 1.84% irq/36-ahci [kernel.kallsyms] [k] handle_irq_event_percpu > 1.14% Xorg [kernel.kallsyms] [k] handle_irq_event_percpu > 0.75% kworker/5:0 [kernel.kallsyms] [k] handle_irq_event_percpu > 0.32% gnome-shell [kernel.kallsyms] [k] handle_irq_event_percpu > 0.25% kworker/5:1H [kernel.kallsyms] [k] handle_irq_event_percpu > 0.25% Media D~ode #10 [kernel.kallsyms] [k] handle_irq_event_percpu > 0.19% ImageDe~er #330 [kernel.kallsyms] [k] handle_irq_event_percpu > 0.07% pulseaudio [kernel.kallsyms] [k] handle_irq_event_percpu > > The cycles were with -e cycles:pp, so I think that iret would have > shown up if there were enough IRQs to cause the problem. > > I'll build a kernel with latencytop. > I just caught call_rwsem_down_write_failed for 5379 ms in khugepaged (holy crap) and radeon_fence_default_wait for 489.2ms in Xorg. Turning off THP gets rid of the khugepaged thing. The 489.2ms is radeon_fence_default_wait is amazingly reproducible -- I've seen that exact number three times now. > --Andy -- Andy Lutomirski AMA Capital Management, LLC _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
