[dpdk-dev] [DPDK-memory] how qemu waste such long time under dpdk huge page envriment?

[Sam]

Additional, this is DPDK-QEMU enviroment.

2017-06-19 11:12 GMT+08:00 Sam <batmanustc at gmail.com>:

> Hi,
>
> I print all system call by `strace -f -T -tt -e trace=all -o output.txt
> $QEMU_CMD`, and I found this:
>
> 5900  11:08:11.288701 nanosleep({0, 10000000}, 0x7ff103c13a80) = 0
>> <0.010171>
>> 5900  11:08:11.299052 futex(0x7ff10be24340, FUTEX_WAIT_PRIVATE, 2, NULL
>> <unfinished ...>
>> 5899  11:08:20.138492 rt_sigaction(SIGBUS, {0x7ff10b5b1040, [],
>> SA_RESTORER|SA_SIGINFO, 0x7ff1085fd100}, NULL, 8) = 0 <0.000012>
>> 5899  11:08:20.138598 rt_sigprocmask(SIG_SETMASK, [BUS USR1 ALRM IO],
>> NULL, 8) = 0 <0.000008>
>> 5899  11:08:20.138646 mmap(NULL, 266240, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff10b380000 <0.000013>
>> 5899  11:08:20.138793 mmap(NULL, 266240, PROT_READ|PROT_WRITE,
>> MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7ff10b33f000 <0.000009>
>
>
> I don't know who call `futex`, and why waste such long time. And for
> `mmap` system call, I don't found this system call waste too much time.
>
> WHY....
>
>
> 2017-06-16 16:59 GMT+08:00 Bruce Richardson <bruce.richardson at intel.com>:
>
>> On Fri, Jun 16, 2017 at 04:26:40PM +0800, Sam wrote:
>> > BTW, while running ovs-dpdk, this log is also take long time, does that
>> > mean dpdk request large memory take long time?
>> >
>> > EAL: Setting up physically contiguous memory...
>> >
>>
>> When running with 1G pages, I found that the mmap system call takes a
>> considerable amount of time to execute. I think this is due to the
>> kernel zero-ing out the 1G pages. IIRC on one system I measured it as
>> taking
>> about 0.4 seconds per 1G page.
>>
>> /Bruce
>>
>> >
>> > 2017-06-16 16:11 GMT+08:00 Sam <batmanustc at gmail.com>:
>> >
>> > > Hi all,
>> > >
>> > > I'm running `QEMU_CMD ...` to create a vm under dpdk huge page
>> envriment
>> > > (which set huge page 1G). And I enable all events in qemu.
>> > >
>> > > For qemu and ovs-dpdk(ovs-2.4.9 with dpdk-2.2.0) environment, detail
>> log
>> > > is:
>> > >
>> > > > 30012 at 1497443246.678304:object_dynamic_cast_assert
>> > > qemu:memory-region->qemu:memory-region (/home/hu
>> > > > anghuai/cloud/contrib/qemu-2.6.0/memory.c:1076:memory_region
>> _initfn)
>> > > > 30012 at 1497443256.274866:object_dynamic_cast_assert
>> > > qio-channel-socket->qio-channel-socket (io/chann
>> > > > el-socket.c:389:qio_channel_socket_init)
>> > >
>> > >
>> > > I don't know why qemu doing 'memory_region_initfn' function in this 10
>> > > second, does anyone know this?
>> > >
>> > > static void memory_region_initfn(Object *obj)
>> > >> {
>> > >>     MemoryRegion *mr = MEMORY_REGION(obj);
>> > >>     ObjectProperty *op;
>> > >>     mr->ops = &unassigned_mem_ops;
>> > >>     mr->enabled = true;
>> > >>     mr->romd_mode = true;
>> > >>     mr->global_locking = true;
>> > >>     mr->destructor = memory_region_destructor_none;
>> > >>     QTAILQ_INIT(&mr->subregions);
>> > >>     QTAILQ_INIT(&mr->coalesced);
>> > >>     op = object_property_add(OBJECT(mr), "container",
>> > >>                              "link<" TYPE_MEMORY_REGION ">",
>> > >>                              memory_region_get_container,
>> > >>                              NULL, /* memory_region_set_container */
>> > >>                              NULL, NULL, &error_abort);
>> > >>     op->resolve = memory_region_resolve_container;
>> > >>     object_property_add(OBJECT(mr), "addr", "uint64",
>> > >>                         memory_region_get_addr,
>> > >>                         NULL, /* memory_region_set_addr */
>> > >>                         NULL, NULL, &error_abort);
>> > >>     object_property_add(OBJECT(mr), "priority", "uint32",
>> > >>                         memory_region_get_priority,
>> > >>                         NULL, /* memory_region_set_priority */
>> > >>                         NULL, NULL, &error_abort);
>> > >>     object_property_add_bool(OBJECT(mr), "may-overlap",
>> > >>                              memory_region_get_may_overlap,
>> > >>                              NULL, /* memory_region_set_may_overlap
>> */
>> > >>                              &error_abort);
>> > >>     object_property_add(OBJECT(mr), "size", "uint64",
>> > >>                         memory_region_get_size,
>> > >>                         NULL, /* memory_region_set_size, */
>> > >>                         NULL, NULL, &error_abort);
>> > >> }
>> > >
>> > >
>> > > Thank you~
>> > >
>>
>
>