1 file changed, 20 insertions, 9 deletions
diff --git a/source/ui-tree.c b/source/ui-tree.c
index b5a5556c..bc5986b7 100644
--- a/source/ui-tree.c
+++ b/source/ui-tree.c
@@ -13,6 +13,9 @@
 #include "html.h"
 #include "ui-shared.h"
 
+/* Bytes shown per row of the binary hex dump. */
+#define HEXDUMP_ROW_BYTES 32
+
 struct tree_ls_entry {
 	struct object_id oid;
 	char *name;
@@ -77,18 +80,26 @@ static void print_text_buffer(const char *name, char *buf, unsigned long size)
 static void print_binary_buffer(char *buf, unsigned long size)
 {
 	unsigned long ofs, idx;
-	static char ascii[ROWLEN + 1];
+	char ascii[HEXDUMP_ROW_BYTES + 1];
+	struct strbuf row = STRBUF_INIT;
 
 	html("<table summary='blob content' class='bin-blob'>\n");
 	html("<tr><th>ofs</th><th>hex dump</th><th>ascii</th></tr>");
-	for (ofs = 0; ofs < size; ofs += ROWLEN, buf += ROWLEN) {
-		htmlf("<tr><td class='right'>%04lx</td><td class='hex'>", ofs);
-		for (idx = 0; idx < ROWLEN && ofs + idx < size; idx++)
-			htmlf("%*s%02x",
-			      idx == 16 ? 4 : 1, "",
-			      buf[idx] & 0xff);
-		html(" </td><td class='hex'>");
-		for (idx = 0; idx < ROWLEN && ofs + idx < size; idx++)
+	for (ofs = 0; ofs < size; ofs += HEXDUMP_ROW_BYTES, buf += HEXDUMP_ROW_BYTES) {
+		// One write per row rather than one per byte. At the default
+		// blob limit the per-byte form spent almost all of its time in
+		// the kernel, which made a single request for a large binary
+		// blob far more expensive than the page it produced.
+		strbuf_reset(&row);
+		strbuf_addf(&row, "<tr><td class='right'>%04lx</td><td class='hex'>", ofs);
+		for (idx = 0; idx < HEXDUMP_ROW_BYTES && ofs + idx < size; idx++)
+			strbuf_addf(&row, "%*s%02x",
+				    idx == 16 ? 4 : 1, "",
+				    buf[idx] & 0xff);
+		strbuf_addstr(&row, " </td><td class='hex'>");
+		html_raw(row.buf, row.len);
+
+		for (idx = 0; idx < HEXDUMP_ROW_BYTES && ofs + idx < size; idx++)
 			ascii[idx] = isgraph((unsigned char)buf[idx]) ? buf[idx] : '.';
 		ascii[idx] = '\0';
 		html_txt(ascii);