Bug 97367

Summary: k520 card produce high volume of IRQ
Product: xorg Reporter: Mathieu Maret <mmaret>
Component: Driver/nouveauAssignee: Nouveau Project <nouveau>
Status: NEW --- QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium    
Version: unspecified   
Hardware: Other   
OS: All   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
dmesg
none
vbios ROM
none
dmesg with debug (nouveau.debug=debug drm.debug=0xe)
none
perf report from perf record -ag
none
perf report from perf record -g -C 7
none
result from 'cat /proc/interrupts > irq ; sleep 1; cat /proc/interrupts >>irq'
none
Tracing using ftrace during 1sec none

Description Mathieu Maret 2016-08-16 14:53:01 UTC
Created attachment 125818 [details]
dmesg

Amazon propose computer with k520(GK104) GPU for virtualisation (Xen).
You can use Ubuntu LTS on it for example.
When inserting the nouveau driver, /proc/interrupts report that nvkm is doing ~100000 interrupts/sec.

This have been tested on kernel 4.4.0 and 4.4.13.

On amazon, you do not control the real hardware where your system will be run. It appear that sometimes, this issue do not happen. May be this could be due to vbios version ?

Forcing nouveau in headless mode (modeset=2) produce a normal amount of IRQ.
Comment 1 Mathieu Maret 2016-08-16 14:53:33 UTC
Created attachment 125819 [details]
vbios ROM
Comment 2 Mathieu Maret 2016-08-16 16:28:30 UTC
Created attachment 125821 [details]
dmesg with debug (nouveau.debug=debug drm.debug=0xe)
Comment 3 Mathieu Maret 2016-08-16 16:31:26 UTC
With another try having modeset=2 does not produce a normal amount of IRQ.
Sorry for the error, it should be due to the randomness of the issue :/
Comment 4 Mathieu Maret 2016-08-18 08:16:18 UTC
Created attachment 125864 [details]
perf report from perf record -ag
Comment 5 Mathieu Maret 2016-08-18 08:17:14 UTC
Created attachment 125865 [details]
perf report from perf record -g -C 7
Comment 6 Mathieu Maret 2016-08-18 08:17:43 UTC
Created attachment 125866 [details]
result from 'cat /proc/interrupts > irq ; sleep 1; cat /proc/interrupts >>irq'
Comment 7 Mathieu Maret 2016-08-18 08:22:08 UTC
The irq file show that the IRQ on nvkm happens 140954 times in 1 sec.
The perf reports does not show things related to nvkm, but I may not have use the right options for perf
Comment 8 Mathieu Maret 2017-02-06 15:35:11 UTC
Disabling MSI interrupts (with config="NvMSI=0") reduce the number of IRQ to about 1k/s
Comment 9 Mathieu Maret 2017-02-08 15:44:20 UTC
Created attachment 129412 [details]
Tracing using ftrace during 1sec
Comment 10 Mathieu Maret 2017-02-08 16:54:05 UTC
This issue can be reproduce on 4.10-rc10

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