Re: stalls with concurrent host name resolvers

Hi Arvid,

Arvid Norberg <arvid-M9ekpT6mRt2zQB+pC5nmwQ@xxxxxxxxxxxxxxxx> wrote:
> Ok, it happens every time for me. I did a testrun with 10
> io_services  (and afaik that means 10 host resolver threads).
> Most host resolver  threads appeared to be blocked at this
> point:
>
> #0    0x9000ab48 in mach_msg_trap
> #1    0x9000aa9c in mach_msg
> #2    0x9002beb0 in _lookup_all_secure
> #3    0x9002bdbc in _lookup_all
> #4    0x9005a564 in lu_gethostbyname
> #5    0x90078324 in getipnodebyname

Hmm, well i'd guess it is an OS problem if it's all the way down
in there. When I get some time I will write a test program that
just calls getipnodebyname in a loop from a lot of different
threads, to confirm whether the problem is unrelated to asio.

Any suggestions as to a workaround? I could serialise all calls
to getipnodebyname using a mutex, but in that case I may as well
be using the non-thread-safe getaddrinfo!

Cheers,
Chris



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