diff --git a/src/log.zig b/src/log.zig
new file mode 100644
index 0000000000000000000000000000000000000000..f5679efacfbad7cc392959eb53398f4e28114122
--- /dev/null
+++ b/src/log.zig
@@ -0,0 +1,19 @@
+const std = @import("std");
+const tracer = @import("./mod.zig");
+const log = std.log.scoped(.tracer);
+
+pub fn init() void {}
+
+pub fn deinit() void {}
+
+pub fn init2() void {}
+
+pub fn deinit2() void {}
+
+pub inline fn trace_begin(ctx: tracer.Ctx) void {
+    log.debug("{s}:{d}:{d} ({s})", .{ ctx.src.file, ctx.src.line, ctx.src.column, ctx.src.fn_name });
+}
+
+pub inline fn trace_end(ctx: tracer.Ctx) void {
+    _ = ctx;
+}
diff --git a/src/mod.zig b/src/mod.zig
index 95a0b682a71942e4010a9c8ee96461fb9a3b53a3..7ebf7a1c3c4255b35ca72ba6e657e317de778fa6 100644
--- a/src/mod.zig
+++ b/src/mod.zig
@@ -1 +1,42 @@
 const std = @import("std");
+const root = @import("root");
+const impl = std.meta.globalOption("tracer_impl", type) orelse none;
+
+var started = false;
+
+pub const none = @import("./none.zig");
+pub const log = @import("./log.zig");
+pub const spall = @import("./spall.zig");
+
+pub fn init() !void {
+    impl.init();
+}
+
+pub fn deinit() void {
+    impl.deinit();
+}
+
+pub fn init2() !void {
+    impl.init2();
+    started = true;
+}
+
+pub fn deinit2() void {
+    impl.deinit2();
+}
+
+pub inline fn trace(src: std.builtin.SourceLocation) Ctx {
+    const ctx = Ctx{
+        .src = src,
+    };
+    if (started) impl.trace_begin(ctx);
+    return ctx;
+}
+
+pub const Ctx = struct {
+    src: std.builtin.SourceLocation,
+
+    pub inline fn end(self: Ctx) void {
+        if (started) impl.trace_end(self);
+    }
+};
diff --git a/src/none.zig b/src/none.zig
new file mode 100644
index 0000000000000000000000000000000000000000..154a721a8969c9c465ece986f2e661a6093f2cc7
--- /dev/null
+++ b/src/none.zig
@@ -0,0 +1,19 @@
+const std = @import("std");
+const tracer = @import("./mod.zig");
+const log = std.log.scoped(.tracer);
+
+pub fn init() void {}
+
+pub fn deinit() void {}
+
+pub fn init2() void {}
+
+pub fn deinit2() void {}
+
+pub inline fn trace_begin(ctx: tracer.Ctx) void {
+    _ = ctx;
+}
+
+pub inline fn trace_end(ctx: tracer.Ctx) void {
+    _ = ctx;
+}
diff --git a/src/spall.zig b/src/spall.zig
new file mode 100644
index 0000000000000000000000000000000000000000..ad4237d74bd367a4cf03b02205e10b193daeb91b
--- /dev/null
+++ b/src/spall.zig
@@ -0,0 +1,66 @@
+const std = @import("std");
+const tracer = @import("./mod.zig");
+const alloc = std.heap.c_allocator;
+const log = std.log.scoped(.tracer);
+const root = @import("root");
+const trim_count = root.build_options.src_file_trimlen;
+
+var pid: std.os.linux.pid_t = undefined;
+threadlocal var tid: std.os.linux.pid_t = undefined;
+threadlocal var path: []const u8 = undefined;
+threadlocal var file: std.fs.File = undefined;
+
+pub fn init() void {
+    pid = std.os.linux.getpid();
+}
+
+pub fn deinit() void {
+    //
+}
+
+pub fn init2() void {
+    tid = std.os.linux.gettid();
+
+    path = std.fmt.allocPrint(alloc, "/data/trace.{d}.{d}.spall.jsonl", .{ pid, tid }) catch @panic("oom");
+    file = std.fs.cwd().createFile(path, .{}) catch @panic("create fail");
+    file.writer().writeAll("[\n") catch @panic("[");
+}
+
+pub fn deinit2() void {
+    defer alloc.free(path);
+    defer file.close();
+
+    file.writer().writeAll("]\n") catch {};
+    log.debug("{s}", .{path});
+}
+
+pub inline fn trace_begin(ctx: tracer.Ctx) void {
+    file.writer().print(
+        \\{{"cat":"function", "name":"{s}:{d}:{d} ({s})", "ph": "B", "pid": {d}, "tid": {d}, "ts": {d}}},
+        \\
+    ,
+        .{
+            if (ctx.src.file[0] == '/') ctx.src.file[trim_count..] else ctx.src.file,
+            ctx.src.line,
+            ctx.src.column,
+            ctx.src.fn_name,
+            pid,
+            tid,
+            std.time.microTimestamp(),
+        },
+    ) catch {};
+}
+
+pub inline fn trace_end(ctx: tracer.Ctx) void {
+    _ = ctx;
+    file.writer().print(
+        \\{{"cat":"function", "ph": "E", "pid": {d}, "tid": {d}, "ts": {d}}},
+        \\
+    ,
+        .{
+            pid,
+            tid,
+            std.time.microTimestamp(),
+        },
+    ) catch {};
+}