agent: Avoid tight timer tick when possible.

* agent/gpg-agent.c (need_tick): Evaluate whether the short-phase
handle_tick() is needed.
(handle_connections): On each cycle of the select loop, adjust whether
we should call handle_tick() or not.
(start_connection_thread_ssh, do_start_connection_thread): Signal the
main loop when the child terminates.
* agent/call-scd.c (start_scd): Call interrupt_main_thread_loop() once
the scdaemon thread context has started up.

--

With this change, an idle gpg-agent that has no scdaemon running only
wakes up once a minute (to check_own_socket).

Thanks to Ian Jackson and NIIBE Yutaka who helped me improve some of
the blocking and corner cases.

Signed-off-by: Daniel Kahn Gillmor <[email protected]>

Gbp-Pq: Topic gpg-agent-idling
Gbp-Pq: Name agent-Avoid-tight-timer-tick-when-possible.patch

1 files changed, 2 insertions, 0 deletions

diff --git a/agent/call-scd.c b/agent/call-scd.c
index 6438693af..ee69bb4c3 100644
--- a/agent/call-scd.c
+++ b/agent/call-scd.c
@@ -414,6 +414,8 @@ start_scd (ctrl_t ctrl)
 
   primary_scd_ctx = ctx;
   primary_scd_ctx_reusable = 0;
+  /* notify the main loop that something has changed */
+  interrupt_main_thread_loop ();
 
  leave:
   xfree (abs_homedir);