[OPTIM] session: don't recheck analysers when buffer flags have not changed

Analysers were re-evaluated when some flags were still present in the
buffers, even if they had not changed since previous pass, resulting
in a waste of CPU cycles.

Ensuring that the flags have changed has saved some useless calls :

  function            min calls per session (before -> after)

  http_request_forward_body       5 -> 4
  http_response_forward_body      3 -> 2
  http_sync_req_state            10 -> 8
  http_sync_res_state             8 -> 6
  http_resync_states              8 -> 6

diff --git a/src/session.c b/src/session.c
index 9beb06caedb9e130cf73989bedbe0842fc2b50b4..c34ed9f65a8333375d30820e93c5e13833d0f080 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -1214,8 +1214,8 @@ struct task *process_session(struct task *t)
        s->req->flags &= ~BF_READ_NOEXP;
 
        /* Keep a copy of req/rep flags so that we can detect shutdowns */
-       rqf_last = s->req->flags;
-       rpf_last = s->rep->flags;
+       rqf_last = s->req->flags & ~BF_MASK_ANALYSER;
+       rpf_last = s->rep->flags & ~BF_MASK_ANALYSER;
 
        /* we don't want the stream interface functions to recursively wake us up */
        if (s->req->prod->owner == t)
@@ -1364,7 +1364,7 @@ struct task *process_session(struct task *t)
 
  resync_request:
        /* Analyse request */
-       if ((s->req->flags & BF_MASK_ANALYSER) ||
+       if (((s->req->flags & ~rqf_last) & BF_MASK_ANALYSER) ||
            ((s->req->flags ^ rqf_last) & BF_MASK_STATIC) ||
            s->si[0].state != rq_prod_last ||
            s->si[1].state != rq_cons_last) {
@@ -1537,7 +1537,7 @@ struct task *process_session(struct task *t)
                        goto resync_response;
                }
        }
-       else if ((s->rep->flags & BF_MASK_ANALYSER) ||
+       else if (((s->rep->flags & ~rpf_last) & BF_MASK_ANALYSER) ||
                 (s->rep->flags ^ rpf_last) & BF_MASK_STATIC ||
                 s->si[0].state != rp_cons_last ||
                 s->si[1].state != rp_prod_last) {
@@ -1627,7 +1627,7 @@ struct task *process_session(struct task *t)
         * we're just in a data phase here since it means we have not
         * seen any analyser who could set an error status.
         */
-       if (!(s->flags & SN_ERR_MASK)) {
+       if (unlikely(!(s->flags & SN_ERR_MASK))) {
                if (s->req->flags & (BF_READ_ERROR|BF_READ_TIMEOUT|BF_WRITE_ERROR|BF_WRITE_TIMEOUT)) {
                        /* Report it if the client got an error or a read timeout expired */
                        s->req->analysers = 0;