diff --git a/.github/scripts/perf_comment.py b/.github/scripts/perf_comment.py
index c4586927243e..659421ae0818 100644
--- a/.github/scripts/perf_comment.py
+++ b/.github/scripts/perf_comment.py
@@ -42,18 +42,29 @@ def is_significant(m):
     return abs(m["delta_pct"]) >= THRESHOLDS.get(m["method"], 0.1)
 
 
-# Stage rows (frontend/backend) shown as base%/head% shares of their group.
+# Stage rows (frontend/backend) shown as base%/head% shares with pp delta.
 def breakdown(children):
     base_total = sum(c["base"] for c in children)
     head_total = sum(c["head"] for c in children)
     if head_total <= 0:
         return []
-    return ["| ↳ {} | {} | {} | {} |".format(
-        c["label"],
-        fmt_share(c["base"], base_total),
-        fmt_share(c["head"], head_total),
-        fmt_delta(c["delta_pct"]),
-    ) for c in children]
+    rows = []
+    for c in children:
+        base_pct = c["base"] / base_total * 100 if base_total > 0 else 0
+        head_pct = c["head"] / head_total * 100 if head_total > 0 else 0
+        pp = head_pct - base_pct
+        if abs(pp) < 0.5:
+            delta_str = "~0pp"
+        else:
+            sign = "+" if pp > 0 else ""
+            delta_str = f"{sign}{pp:.0f}pp"
+        rows.append("| ↳ {} | {} | {} | {} |".format(
+            c["label"],
+            fmt_share(c["base"], base_total),
+            fmt_share(c["head"], head_total),
+            delta_str,
+        ))
+    return rows
 
 
 def render(results):
diff --git a/tools/perfrunner/source/metrics.d b/tools/perfrunner/source/metrics.d
index 96a62e22da07..888a980a91e1 100644
--- a/tools/perfrunner/source/metrics.d
+++ b/tools/perfrunner/source/metrics.d
@@ -30,6 +30,10 @@ immutable MetricDef[] initials = [
     MetricDef("phobos_max_rss",              "peak RSS (compile Phobos)",  "kb",    "time -v"),
     MetricDef("phobos_stage_frontend", "frontend (parse+sema)",     "us", "time-trace", "compile_phobos_instr"),
     MetricDef("phobos_stage_backend",  "backend (inline+codegen)",  "us", "time-trace", "compile_phobos_instr"),
+    MetricDef("phobos_stage_parse",    "parse",                     "us", "time-trace", "phobos_stage_frontend"),
+    MetricDef("phobos_stage_sema",     "semantic analysis",         "us", "time-trace", "phobos_stage_frontend"),
+    MetricDef("phobos_stage_inline",   "inlining",                  "us", "time-trace", "phobos_stage_backend"),
+    MetricDef("phobos_stage_codegen",  "code generation",           "us", "time-trace", "phobos_stage_backend"),
 ];
 
 // Measure every metric for one dmd binary. `tag` ("base"/"head")
@@ -53,6 +57,10 @@ long[string] measure(string dmd, string workload, string phobos, string tmp, str
     auto st = stages(dmd, phobosFlags, stdPackage, tmp, tag ~ "-phobos");
     m["phobos_stage_frontend"] = st.get("stage_frontend_us", 0);
     m["phobos_stage_backend"]  = st.get("stage_backend_us", 0);
+    m["phobos_stage_parse"]    = st.get("stage_parse_us", 0);
+    m["phobos_stage_sema"]     = st.get("stage_sema_us", 0);
+    m["phobos_stage_inline"]   = st.get("stage_inline_us", 0);
+    m["phobos_stage_codegen"]  = st.get("stage_codegen_us", 0);
     return m;
 }
 
diff --git a/tools/perfrunner/source/timetrace.d b/tools/perfrunner/source/timetrace.d
index b637c5d15579..fa63708edf81 100644
--- a/tools/perfrunner/source/timetrace.d
+++ b/tools/perfrunner/source/timetrace.d
@@ -1,6 +1,6 @@
 module timetrace;
 
-import std.algorithm : canFind;
+
 import std.file : readText;
 import std.json : parseJSON;
 import std.path : buildPath;
@@ -9,24 +9,33 @@ import std.process : execute;
 // The top-level -ftime-trace spans grouped into frontend/backend. These names
 // match main.d's generic phase spans; they don't overlap, so summing them
 // partitions the compile without double-counting the nested per-symbol events.
-private immutable string[] frontendSpans = ["Parsing", "Semantic analysis"];
-private immutable string[] backendSpans  = ["Inlining", "Code generation"];
-
 // Sum the duration (microseconds) of the top-level spans in each bucket.
+// Returns both coarse (frontend/backend) and fine (parse/sema/inline/codegen).
 long[string] parseStages(string trace)
 {
-    long frontend, backend;
+    long parse, sema, inline, codegen;
     foreach (e; parseJSON(trace)["traceEvents"].array)
     {
         if (e["ph"].str != "X")
             continue;
         auto name = e["name"].str;
-        if (frontendSpans.canFind(name))
-            frontend += e["dur"].integer;
-        else if (backendSpans.canFind(name))
-            backend += e["dur"].integer;
+        if (name == "Parsing")
+            parse += e["dur"].integer;
+        else if (name == "Semantic analysis")
+            sema += e["dur"].integer;
+        else if (name == "Inlining")
+            inline += e["dur"].integer;
+        else if (name == "Code generation")
+            codegen += e["dur"].integer;
     }
-    return ["stage_frontend_us": frontend, "stage_backend_us": backend];
+    return [
+        "stage_frontend_us": parse + sema,
+        "stage_backend_us":  inline + codegen,
+        "stage_parse_us":    parse,
+        "stage_sema_us":     sema,
+        "stage_inline_us":   inline,
+        "stage_codegen_us":  codegen,
+    ];
 }
 
 // Compile the workload with -ftime-trace and read the per-stage durations.
@@ -57,4 +66,8 @@ unittest
     auto s = parseStages(sample);
     assert(s["stage_frontend_us"] == 400);
     assert(s["stage_backend_us"] == 100);
+    assert(s["stage_parse_us"] == 100);
+    assert(s["stage_sema_us"] == 300);
+    assert(s["stage_inline_us"] == 20);
+    assert(s["stage_codegen_us"] == 80);
 }