MINOR: hpack: optimize header encoding for short names

For unknown fields, since we know that most of them are less than 127
characters, we don't need to go through the loop and can instead directly
emit the one-byte length encoding. This increases the request rate by
approximately 0.5%.

diff --git a/src/hpack-enc.c b/src/hpack-enc.c
index 73a5fd16718f76db5a0891055ed95dcaa9cca122..dd0d0ab247963a87e1ab6c2e8dd4f7ee7033fefb 100644 (file)
--- a/src/hpack-enc.c
+++ b/src/hpack-enc.c
@@ -114,6 +114,12 @@ int hpack_encode_header(struct buffer *out, const struct ist n,
                out->area[len++] = 0x58; // literal with indexing -- name="cache-control" (idx 24)
        else if (isteq(n, ist("content-length")))
                out->area[len++] = 0x5c; // literal with indexing -- name="content-length" (idx 28)
+       else if (likely(n.len < 127 && len + 1 + n.len <= size)) {
+               out->area[len++] = 0x00;      /* literal without indexing -- new name */
+               out->area[len++] = n.len;     /* single-byte length encoding */
+               ist2bin(out->area + len, n);
+               len += n.len;
+       }
        else if (len_to_bytes(n.len) && len + 1 + len_to_bytes(n.len) + n.len <= size) {
                out->area[len++] = 0x00;      /* literal without indexing -- new name */
                len = hpack_encode_len(out->area, len, n.len);