Improve commentary for adaptive read buffering.

1 files changed, 13 insertions, 4 deletions

diff --git a/src/process.c b/src/process.c
index 5f756f4db05..bee61b5505a 100644
--- a/src/process.c
+++ b/src/process.c
@@ -272,17 +272,19 @@ int update_tick;
 #define READ_OUTPUT_DELAY_MAX       (READ_OUTPUT_DELAY_INCREMENT * 5)
 #define READ_OUTPUT_DELAY_MAX_MAX   (READ_OUTPUT_DELAY_INCREMENT * 7)
 
-/* Number of processes which might be delayed.  */
+/* Number of processes which have a non-zero read_output_delay,
+   and therefore might be delayed for adaptive read buffering.  */
 
 static int process_output_delay_count;
 
-/* Non-zero if any process has non-nil process_output_skip.  */
+/* Non-zero if any process has non-nil read_output_skip.  */
 
 static int process_output_skip;
 
 /* Non-nil means to delay reading process output to improve buffering.
    A value of t means that delay is reset after each send, any other
-   non-nil value does not reset the delay.  */
+   non-nil value does not reset the delay.  A value of nil disables
+   adaptive read buffering completely.  */
 static Lisp_Object Vprocess_adaptive_read_buffering;
 #else
 #define process_output_delay_count 0
@@ -4319,6 +4321,11 @@ wait_reading_process_output (time_limit, microsecs, read_kbd, do_display,
 #endif
 
 #ifdef ADAPTIVE_READ_BUFFERING
+          /* Set the timeout for adaptive read buffering if any
+             process has non-nil read_output_skip and non-zero
+             read_output_delay, and we are not reading output for a
+             specific wait_channel.  It is not executed if
+             Vprocess_adaptive_read_buffering is nil.  */
           if (process_output_skip && check_delay > 0)
             {
               int usecs = EMACS_USECS (timeout);
@@ -4329,6 +4336,8 @@ wait_reading_process_output (time_limit, microsecs, read_kbd, do_display,
                   proc = chan_process[channel];
                   if (NILP (proc))
                     continue;
+                  /* Find minimum non-zero read_output_delay among the
+                     processes with non-nil read_output_skip.  */
                   if (XINT (XPROCESS (proc)->read_output_delay) > 0)
                     {
                       check_delay--;
@@ -6711,7 +6720,7 @@ init_process ()
 #endif /* HAVE_SOCKETS */
 
 #if defined (DARWIN) || defined (MAC_OSX)
-  /* PTYs are broken on Darwin < 6, but are sometimes useful for interactive 
+  /* PTYs are broken on Darwin < 6, but are sometimes useful for interactive
      processes.  As such, we only change the default value.  */
  if (initialized)
   {