curl_easy_perform: gradually increase the delay time

Instead of going 50,100,150 etc millisecond delay time when nothing has been found to do or wait for, we now start lower and double each loop as in 4,8,16,32 etc. This lowers the minimum wait without sacrifizing the longer wait too much with unnecessary CPU cycles burnt. Bug: http://curl.haxx.se/mail/lib-2013-07/0103.html Reported-by: Andreas Malzahn
curl · Jul 19, 2013 · d529f38 · d529f38 · remoe · Jul 30, 2013
1 parent e2e9248
commit d529f38
Showing 1 changed file with 1 addition and 3 deletions.
diff --git a/lib/easy.c b/lib/easy.c
@@ -539,9 +539,7 @@ CURLcode curl_easy_perform(CURL *easy)
         if(curlx_tvdiff(after, before) <= 10) {
           without_fds++;
           if(without_fds > 2) {
-            int sleep_ms = without_fds * 50;
+            int sleep_ms = without_fds < 10 ? (1 << (without_fds-1)): 1000;
-            if(sleep_ms > 1000)
-              sleep_ms = 1000;
             Curl_wait_ms(sleep_ms);
           }
         }