Re: [libmicrohttpd] Hang with MHD_OPTION_THREAD_POOL_SIZE on Windows
Hi Jonathan,
Hmm. This reads like the 'listen' socket is not properly set to
non-blocking on Windows (or W32 doesn't support non-blocking listen
sockets, which would be worse...).
Could you please check the syscalls MHD makes to setup the listen
socket? It needs to be non-blocking. I don't do W32 development, but
patches would be welcome!
Happy hacking!
Christian
On 12/8/18 1:07 AM, Jonathan McDougall wrote:
> I've been having problems with MHD_OPTION_THREAD_POOL_SIZE on Windows.
> I started with 0.9.55 from vcpkg, but then changed the portfile to use
> 0.9.61 instead. Both give the same results.
>
> Connections to the server hang intermittently. More threads in the pool
> seems to make it hang more often. I think I was able to trace it back to
> a blocking call to accept() in MHD_accept_connection().
>
> What I'm seeing is that all threads block on a select() call in
> MHD_select(). When a connection comes in, *multiple threads* wake up
> at the same time and end up in MHD_accept_connection(). Some of them
> seem to then block on accept().
>
> Repeated calls of curl eventually works, but it can take a dozen calls
> before one goes through with 8 threads in the pool. Threads that are
> blocked in accept() seem to be able to eventually wake up and accept a
> connection.
>
> I'm attaching a short repro below. Executing something like
> 'curl http://127.0.0.1:8080/a' usually hangs. There's nothing special in
> the code, I ripped it out of test_get.c. In fact, test_get.c itself
> hangs in testMultithreadedPoolGet().
>
> I'm using Visual Studio 2019 Preview (16.0 P1) on Windows 10. I'm
> reproducing this on both x86 and x64.
>
>
> #include
> #include
>
> int echo(
> void* cls, struct MHD_Connection* connection, const char* url,
> const char* method, const char* version,
> const char* upload_data, size_t* upload_data_size,
> void** unused)
> {
> static int ptr;
> struct MHD_Response* response;
> int ret;
>
> if (&ptr != *unused)
> {
> *unused = &ptr;
> return MHD_YES;
> }
>
> *unused = NULL;
> response = MHD_create_response_from_buffer(
> strlen(url), (void*)url, MHD_RESPMEM_MUST_COPY);
>
> ret = MHD_queue_response(connection, MHD_HTTP_OK, response);
> MHD_destroy_response(response);
>
> return ret;
> }
>
> int main()
> {
> const unsigned int count = 8;
>
> struct MHD_Daemon* d = MHD_start_daemon(
> MHD_USE_INTERNAL_POLLING_THREAD,
> 8080, NULL, NULL, &echo, NULL,
> MHD_OPTION_THREAD_POOL_SIZE, count,
> MHD_OPTION_END);
>
> getc(stdin);
>
> MHD_stop_daemon(d);
>
> return 0;
> }
>
signature.asc
Description: OpenPGP digital signature
Re: [libmicrohttpd] libmicrohttpd 0.9.62 released
Great work! I'm using thread-pool and I confirm the problem too. Thanks JM for sending the patch solving it and Christian for the p.s note. Cheers On Sat, Dec 8, 2018 at 9:25 PM Christian Grothoff wrote: > Dear all, > > I'm glad to announce the release of GNU libmicrohttpd 0.9.62. > > GNU libmicrohttpd is a small C library that is supposed to make it easy > to run an HTTP server as part of another application. GNU libmicrohttpd > is fully HTTP 1.1 compliant and supports IPv6. Finally, GNU > libmicrohttpd is fast, portable and has a simple API and (without TLS > support and other optional features) a small binary size (~32k). > > This is bugfix *and* feature release. > Changes since version 0.9.61: > * Fixes regression with double-unescaping of URLs > * Adds support for RFC 7616-style digest authentication with > SHA-256 > * Better file-IO buffer size on W32 (performance improvement) > * new compile-time option to build MHD without *any* threading > library (MHD_FEATURE_THREADS) for embedded systems without > thread support > * documentation improvements > > You can download GNU libmicrohttpd from > > * https://ftp.gnu.org/gnu/libmicrohttpd/ and all GNU FTP mirrors. > * Our git repository at https://git.gnunet.org/git/libmicrohttpd.git > > Please report bugs to our bugtracker at https://gnunet.org/bugs/. > > The documentation (including a reference manual and tutorial) can be > found at https://www.gnu.org/software/libmicrohttpd/. > > > Happy hacking! > > Christian > p.s.: The WSA_FLAG_OVERLAPPED-fix posted on the mailinglist earlier > today came literally a minute after the release had been uploaded. > W32 users that use a thread pool should probably add that patch as > well ;-). > -- Silvio Clécio
[libmicrohttpd] libmicrohttpd 0.9.62 released
Dear all, I'm glad to announce the release of GNU libmicrohttpd 0.9.62. GNU libmicrohttpd is a small C library that is supposed to make it easy to run an HTTP server as part of another application. GNU libmicrohttpd is fully HTTP 1.1 compliant and supports IPv6. Finally, GNU libmicrohttpd is fast, portable and has a simple API and (without TLS support and other optional features) a small binary size (~32k). This is bugfix *and* feature release. Changes since version 0.9.61: * Fixes regression with double-unescaping of URLs * Adds support for RFC 7616-style digest authentication with SHA-256 * Better file-IO buffer size on W32 (performance improvement) * new compile-time option to build MHD without *any* threading library (MHD_FEATURE_THREADS) for embedded systems without thread support * documentation improvements You can download GNU libmicrohttpd from * https://ftp.gnu.org/gnu/libmicrohttpd/ and all GNU FTP mirrors. * Our git repository at https://git.gnunet.org/git/libmicrohttpd.git Please report bugs to our bugtracker at https://gnunet.org/bugs/. The documentation (including a reference manual and tutorial) can be found at https://www.gnu.org/software/libmicrohttpd/. Happy hacking! Christian p.s.: The WSA_FLAG_OVERLAPPED-fix posted on the mailinglist earlier today came literally a minute after the release had been uploaded. W32 users that use a thread pool should probably add that patch as well ;-). signature.asc Description: OpenPGP digital signature
