1 files changed, 20 insertions, 0 deletions
diff --git a/test/perf.zig b/test/perf.zig
index e244091c..c639178f 100644
--- a/test/perf.zig
+++ b/test/perf.zig
@@ -46,6 +46,9 @@ const Op = enum {
     page_down,
     wheel,
     edit_char,
+    /// 2 MB appended to the file through 9P, on one open, in 256 KB
+    /// writes: linear, not a copy of the whole buffer per write.
+    body_write,
 
     fn label(o: Op) []const u8 {
         return switch (o) {
@@ -56,10 +59,25 @@ const Op = enum {
             .page_down => "page-down",
             .wheel => "wheel",
             .edit_char => "edit-char",
+            .body_write => "body-2m",
         };
     }
 };
 
+var body_chunk: [256 * 1024]u8 = @splat('y');
+
+/// The body_write gesture: an open of the pane's body, eight 256 KB writes,
+/// a read (which the held writes go in before), the close.
+fn bodyWrite(core: *pardes.Pardes, serial: u32) void {
+    const Node = pardes.ctlfs.Node;
+    const body = Node.of(serial, .body);
+    for (&body_chunk, 0..) |*c, i| c.* = if (i % 64 == 63) '\n' else 'y';
+    const h = core.serveFs(.{ .tag = 1, .op = .open, .node = body, .omode = 1 }).handle;
+    for (0..8) |_| _ = core.serveFs(.{ .tag = 2, .op = .write, .node = body, .handle = h, .data = &body_chunk });
+    _ = core.serveFs(.{ .tag = 3, .op = .getattr, .node = body, .handle = h });
+    _ = core.serveFs(.{ .tag = 4, .op = .release, .node = body, .handle = h, .opened = true });
+}
+
 const TermFixture = struct {
     name: []const u8,
     kb: usize,
@@ -514,12 +532,14 @@ fn measure(op: Op, fx: Fixture, path: []const u8, expected_bytes: usize, reps: u
             .page_down => core.update(.{ .key = .{ .cp = pardes.Key.page_down } }),
             .wheel => core.update(.{ .mouse = .{ .button = .wheel_down, .kind = .press, .col = wheel_col, .row = wheel_row } }),
             .edit_char => core.update(.{ .key = .{ .cp = 'x', .text = "x" } }),
+            .body_write => bodyWrite(core, pane.serial),
         }
         pump(core);
         _ = try frame(core);
         const dt = nowNs() -| t0;
         switch (op) {
             .open => unreachable,
+            .body_write => if (pane.file.?.content.len != before.len + 8 * body_chunk.len) return error.BodyWriteWasNotAppended,
             .render => if (pane.body.cur_row != before.row or pane.body.cur_col != before.col or pane.file.?.content.len != before.len)
                 return error.RenderChangedDocument,
             .key_down => if (pane.body.cur_row != before.row + 1) return error.DownDidNotMove,