PR28708: debuginfod: use MHD_USE_EPOLL for microhttpd threads

Testing on s390x and other architectures indicates that this
configuration reduces thundering-herd wakeups and saturation of a
small number of threads.  The run-debuginfod-webapi-concurrency.sh
test appears solid now.

Signed-off-by: Frank Ch. Eigler <fche@redhat.com>

diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
index dfb5d42..38a389e 100644 (file)
--- a/debuginfod/ChangeLog
+++ b/debuginfod/ChangeLog
@@ -1,3 +1,8 @@
+2022-04-03  Frank Ch. Eigler <fche@redhat.com>
+
+       * debuginfod.cxx (main): Use MHD_USE_EPOLL for libmicrohttpd, to
+       encourage more round-robin dispatch of incoming connections.
+
 2021-12-09  Alexander Kanavin <alex@linutronix.de>
 
        * debuginfod-client.c (cache_clean_default_interval_s): Change type to

diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx
index bb8e8e1..99924d3 100644 (file)
--- a/debuginfod/debuginfod.cxx
+++ b/debuginfod/debuginfod.cxx
@@ -3881,6 +3881,9 @@ main (int argc, char *argv[])
 #else
                                      | MHD_USE_SELECT_INTERNALLY
 #endif
+#ifdef MHD_USE_EPOLL
+                                     | MHD_USE_EPOLL
+#endif
                                      | MHD_USE_DEBUG, /* report errors to stderr */
                                      http_port,
                                      NULL, NULL, /* default accept policy */
@@ -3895,6 +3898,9 @@ main (int argc, char *argv[])
 #else
                                      | MHD_USE_SELECT_INTERNALLY
 #endif
+#ifdef MHD_USE_EPOLL
+                                     | MHD_USE_EPOLL
+#endif
                                      | MHD_USE_IPv6
                                      | MHD_USE_DEBUG, /* report errors to stderr */
                                      http_port,