[master] 4b15ca8f0 vsl: New Timestamp:Process for backend tasks

[Dridi Boukelmoune]

commit 4b15ca8f0ae89677e52206a12a2fa9e1fa7c93e4
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Thu Oct 22 14:30:11 2020 +0200

    vsl: New Timestamp:Process for backend tasks
    
    Similarly to Timestamp:Fetch, it is otherwise not possible to distinguish
    between time spent in VCL and time spent strictly fetching the response
    body.

diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index 02dd19f66..4d7b1547c 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -518,6 +518,7 @@ vbf_stp_startfetch(struct worker *wrk, struct busyobj *bo)
 		return (F_STP_ERROR);
 	}
 
+	VSLb_ts_busyobj(bo, "Process", W_TIM_real(wrk));
 	assert(oc->boc->state <= BOS_REQ_DONE);
 	if (oc->boc->state != BOS_REQ_DONE) {
 		bo->req = NULL;
diff --git a/doc/sphinx/reference/vsl.rst b/doc/sphinx/reference/vsl.rst
index 00cec7fc6..e1d608edb 100644
--- a/doc/sphinx/reference/vsl.rst
+++ b/doc/sphinx/reference/vsl.rst
@@ -98,6 +98,9 @@ Bereq
 Beresp
 	Backend response headers received.
 
+Process
+	Processing finished, ready to fetch the response body.
+
 BerespBody
 	Backend response body received.