Re: [Qemu-devel] Freeze / spin in virtio blk...flatview do translate

[Frank Yang]

And this one:

https://github.com/qemu/qemu/commit/a411c84b561baa94b28165c52f21c33517ee8f59

On Sat, Sep 15, 2018 at 4:42 PM Frank Yang <address@hidden> wrote:

> I notice at least two commits in upstream QEMU that might impact this:
>
>
> https://github.com/qemu/qemu/commit/ce3a9eaff4e5f29514dba35a001894cb7a238e07#diff-8bfe2ea13d8c6dab17a555f300ac2f66
>
> https://github.com/qemu/qemu/commit/45641dba38f6f44c3ea44c2d1c37b31619276ce3#diff-a9288ea1a561573c7d3036de7d7048e8
>
>
> On Sat, Sep 15, 2018 at 11:41 AM Frank Yang <address@hidden> wrote:
>
>> Hi qemu-devel,
>>
>> So we're using QEMU 2.12 for recent Android Emulator canaryies, and we're
>> seeing a lot of hangs on mac in flatview_translate in qemu 2.12.
>>
>> What would be some pointers for diagnosing excessive I/O?
>>
>> Especially, metrics to see if a system is on the verge of getting into
>> main loop spins.
>>
>> We have not reproduced this hang so far, this is from user crash reports
>> that triggered our hang detector (where 15+ seconds pass without main loop
>> / VCPU threads being able to go back and ping their loopers in main loop /
>> vcpu threads.
>>
>> 0x00000001024e9fcb(qemu-system-x86_64 -exec.c:511)flatview_translate
>> 0x00000001024f2390(qemu-system-x86_64
>> -memory.h:1865)address_space_lduw_internal_cached
>> 0x000000010246ff11(qemu-system-x86_64
>> -virtio-access.h:166)virtio_queue_set_notification
>> 0x00000001024fa2c9(qemu-system-x86_64+ 0x000a72c9)virtio_blk_handle_vq
>> 0x00000001024746ee(qemu-system-x86_64
>> -virtio.c:1521)virtio_queue_host_notifier_aio_read
>> 0x0000000103a5ed8a(qemu-system-x86_64
>> -aio-posix.c:406)aio_dispatch_handlers
>> 0x0000000103a5ecc8(qemu-system-x86_64 -aio-posix.c:437)aio_dispatch
>> 0x0000000103a5c158(qemu-system-x86_64 -async.c:261)aio_ctx_dispatch
>> 0x0000000103a92103(qemu-system-x86_64
>> -gmain.c:3072)g_main_context_dispatch
>> 0x0000000103a5e4ad(qemu-system-x86_64 -main-loop.c:224)main_loop_wait
>> 0x0000000102468ab8(qemu-system-x86_64 -vl.c:2172)main_impl
>> 0x0000000102461a3a(qemu-system-x86_64 -vl.c:3332)run_qemu_main
>> 0x000000010246eef3(qemu-system-x86_64
>> -main.cpp:577)enter_qemu_main_loop(int, char**)
>> 0x00000001062b63a9(libQt5Core.5.dylib
>> -qthread_unix.cpp:344)QThreadPrivate::start(void*)
>> 0x00007fff65118660
>> 0x00007fff6511850c
>> 0x00007fff65117bf8
>> 0x00000001062b623f(libQt5Core.5.dylib+ 0x0002623f)
>>
>> Thanks,
>>
>> Frank
>>
>