λgitsite

perf: httpd writer-flush writes live sub-range without copying

ober

d6c09d8101fdce37f1fa3b1399380c5120114167

diff --git a/dependencies.lock b/dependencies.lock
index 3f03098..e32e9f5 100644
--- a/dependencies.lock
+++ b/dependencies.lock
@@ -1,2 +1,2 @@
 # name repository commit tree
-jerboa-ssl https://git.sr.ht/~lisp/jerboa-ssl 270b858534941baad6420e4906a26c279f4a8678 4d629174bbff9b1cd2ff1aa696be0cd33bf462e4
+jerboa-ssl https://git.sr.ht/~lisp/jerboa-ssl 5c6061c44c79b68438dcaaeb1a2e082a6a7a7199 559c18e3d9d5fd90bfcde88ea2e88f8bf912cba4
diff --git a/lib/jerboa-https/httpd.sls b/lib/jerboa-https/httpd.sls
index 966b868..91426aa 100644
--- a/lib/jerboa-https/httpd.sls
+++ b/lib/jerboa-https/httpd.sls
@@ -373,11 +373,7 @@
   (def (writer-flush! w)
        (let ([pos (writer-pos w)] [buf (writer-buf w)])
          (when (> pos 0)
-           (if (= pos (bytevector-length buf))
-               (conn-write (writer-conn w) buf)
-               (let ([bv (make-bytevector pos)])
-                 (bytevector-copy! buf 0 bv 0 pos)
-                 (conn-write (writer-conn w) bv)))
+           (conn-write-sub (writer-conn w) buf 0 pos)
            (writer-pos-set! w 0))))
   (def (writer-write-byte! w b)
        (let ([pos (writer-pos w)] [buf (writer-buf w)])
diff --git a/src/jerboa-https/httpd.ss b/src/jerboa-https/httpd.ss
index 2516c84..2037141 100644
--- a/src/jerboa-https/httpd.ss
+++ b/src/jerboa-https/httpd.ss
@@ -440,12 +440,10 @@
     (let ([pos (writer-pos w)]
           [buf (writer-buf w)])
       (when (> pos 0)
-        (if (= pos (bytevector-length buf))
-            ;; Whole buffer is live — hand it to the transport without a copy.
-            (conn-write (writer-conn w) buf)
-            (let ([bv (make-bytevector pos)])
-              (bytevector-copy! buf 0 bv 0 pos)
-              (conn-write (writer-conn w) bv)))
+        ;; Write the live sub-range [0,pos) straight to the transport. The
+        ;; full-buffer case is just offset 0 / len cap, so a single sub-range
+        ;; write covers both without ever copying the slice out first.
+        (conn-write-sub (writer-conn w) buf 0 pos)
         (writer-pos-set! w 0))))
 
   (def (writer-write-byte! w b)