diff --git a/Cargo.lock b/Cargo.lock
index c7315d3..efa9e0d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1507,6 +1507,20 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "fxprof-processed-profile"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "25234f20a3ec0a962a61770cfe39ecf03cb529a6e474ad8cff025ed497eda557"
+dependencies = [
+ "bitflags 2.9.1",
+ "debugid",
+ "rustc-hash 2.1.1",
+ "serde",
+ "serde_derive",
+ "serde_json",
+]
+
 [[package]]
 name = "gethostname"
 version = "0.4.3"
@@ -2140,10 +2154,12 @@ dependencies = [
  "egui_extras",
  "elf",
  "fixed",
+ "fxprof-processed-profile",
  "gilrs",
  "hex",
  "image",
  "itertools 0.14.0",
+ "normpath",
  "num-derive",
  "num-traits",
  "oneshot",
@@ -2569,6 +2585,15 @@ dependencies = [
  "minimal-lexical",
 ]
 
+[[package]]
+name = "normpath"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8911957c4b1549ac0dc74e30db9c8b0e66ddcd6d7acc33098f4c63a64a6d7ed"
+dependencies = [
+ "windows-sys 0.59.0",
+]
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.46.0"
diff --git a/Cargo.toml b/Cargo.toml
index 2909eac..e8c5c8c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -22,11 +22,13 @@ egui-notify = "0.20"
 egui-winit = "0.32"
 egui-wgpu = { version = "0.32", features = ["winit"] }
 elf = "0.8"
+fxprof-processed-profile = "0.8"
 fixed = { version = "1.28", features = ["num-traits"] }
 gilrs = { version = "0.11", features = ["serde-serialize"] }
 hex = "0.4"
 image = { version = "0.25", default-features = false, features = ["png"] }
 itertools = "0.14"
+normpath = "1"
 num-derive = "0.4"
 num-traits = "0.2"
 oneshot = "0.1"
diff --git a/src/profiler.rs b/src/profiler.rs
index a9ccb22..62ebac1 100644
--- a/src/profiler.rs
+++ b/src/profiler.rs
@@ -1,15 +1,19 @@
 use std::{
-    collections::HashMap,
     path::PathBuf,
     sync::{Arc, Mutex},
     thread,
 };
 
-use anyhow::{Result, bail};
+use anyhow::Result;
 use tokio::{select, sync::mpsc};
-use wholesym::{SymbolManager, SymbolMap};
 
 use crate::emulator::{EmulatorClient, EmulatorCommand, ProfileEvent, SimEvent, SimId};
+use recording::Recording;
+use state::ProgramState;
+
+mod recording;
+mod state;
+mod symbols;
 
 pub struct Profiler {
     sim_id: SimId,
@@ -182,14 +186,6 @@ enum RecordingAction {
     Cancel,
 }
 
-struct Recording {}
-
-impl Recording {
-    fn new() -> Self {
-        Self {}
-    }
-}
-
 struct ProfilerSession {
     program: Option<ProgramState>,
     recording: Option<Recording>,
@@ -210,8 +206,8 @@ impl ProfilerSession {
     }
 
     fn track_elapsed_cycles(&mut self, cycles: u32) -> Result<()> {
-        if let Some(program) = &mut self.program {
-            program.track_elapsed_cycles(cycles)?;
+        if let (Some(state), Some(recording)) = (&self.program, &mut self.recording) {
+            recording.track_elapsed_cycles(state, cycles);
         }
         Ok(())
     }
@@ -224,126 +220,16 @@ impl ProfilerSession {
     }
 
     fn start_recording(&mut self) {
-        self.recording = Some(Recording::new());
+        if let Some(program) = &self.program {
+            self.recording = Some(Recording::new(program));
+        }
     }
 
     fn finish_recording(&mut self) -> Option<Vec<u8>> {
-        self.recording.take().map(|_| vec![])
+        self.recording.take().map(|r| r.finish())
     }
 
     fn cancel_recording(&mut self) {
         self.recording.take();
     }
 }
-
-struct ProgramState {
-    symbol_map: SymbolMap,
-    call_stacks: HashMap<u16, Vec<StackFrame>>,
-    context_stack: Vec<u16>,
-}
-
-struct StackFrame {
-    #[expect(dead_code)]
-    address: u32,
-    cycles: u64,
-}
-
-const RESET_CODE: u16 = 0xfff0;
-impl ProgramState {
-    async fn new(file_path: PathBuf) -> Result<Self> {
-        let symbol_manager = SymbolManager::with_config(Default::default());
-        let symbol_map = symbol_manager
-            .load_symbol_map_for_binary_at_path(&file_path, None)
-            .await?;
-        let mut call_stacks = HashMap::new();
-        call_stacks.insert(
-            RESET_CODE,
-            vec![StackFrame {
-                address: 0xfffffff0,
-                cycles: 0,
-            }],
-        );
-        Ok(Self {
-            symbol_map,
-            call_stacks,
-            context_stack: vec![RESET_CODE],
-        })
-    }
-
-    fn track_elapsed_cycles(&mut self, cycles: u32) -> Result<()> {
-        let Some(code) = self.context_stack.last() else {
-            return Ok(()); // program is halted, CPU is idle
-        };
-        let Some(stack) = self.call_stacks.get_mut(code) else {
-            bail!("missing stack {code:04x}");
-        };
-        for frame in stack {
-            frame.cycles += cycles as u64;
-        }
-        Ok(())
-    }
-
-    fn track_event(&mut self, event: SimEvent) -> Result<()> {
-        match event {
-            SimEvent::Call(address) => {
-                let Some(code) = self.context_stack.last() else {
-                    bail!("How did we call anything when we're halted?");
-                };
-                let Some(stack) = self.call_stacks.get_mut(code) else {
-                    bail!("missing stack {code:04x}");
-                };
-                let name = self
-                    .symbol_map
-                    .lookup_sync(wholesym::LookupAddress::Svma(address as u64));
-                println!("depth {}: {:x?}", stack.len(), name);
-                stack.push(StackFrame { address, cycles: 0 });
-            }
-            SimEvent::Return => {
-                let Some(code) = self.context_stack.last() else {
-                    bail!("how did we return when we're halted?");
-                };
-                let Some(stack) = self.call_stacks.get_mut(code) else {
-                    bail!("missing stack {code:04x}");
-                };
-                if stack.pop().is_none() {
-                    bail!("returned from {code:04x} but stack was empty");
-                }
-                if stack.is_empty() {
-                    bail!("returned to oblivion");
-                }
-            }
-            SimEvent::Halt => {
-                let Some(RESET_CODE) = self.context_stack.pop() else {
-                    bail!("halted when not in an interrupt");
-                };
-            }
-            SimEvent::Interrupt(code, address) => {
-                // if the CPU was halted before, wake it up now
-                if self.context_stack.is_empty() {
-                    self.context_stack.push(RESET_CODE);
-                }
-
-                self.context_stack.push(code);
-                if self
-                    .call_stacks
-                    .insert(code, vec![StackFrame { address, cycles: 0 }])
-                    .is_some()
-                {
-                    bail!("{code:04x} fired twice");
-                }
-            }
-            SimEvent::Reti => {
-                let Some(code) = self.context_stack.pop() else {
-                    bail!("RETI when halted");
-                };
-                if code == RESET_CODE {
-                    bail!("RETI when not in interrupt");
-                }
-                if self.call_stacks.remove(&code).is_none() {
-                    bail!("{code:04x} popped but never called");
-                }
-            }
-        }
-        Ok(())
-    }
-}
diff --git a/src/profiler/recording.rs b/src/profiler/recording.rs
new file mode 100644
index 0000000..d4836eb
--- /dev/null
+++ b/src/profiler/recording.rs
@@ -0,0 +1,114 @@
+use std::collections::HashMap;
+
+use fxprof_processed_profile::{
+    CategoryHandle, CpuDelta, Frame, FrameFlags, FrameInfo, ProcessHandle, Profile,
+    ReferenceTimestamp, SamplingInterval, StackHandle, ThreadHandle, Timestamp,
+};
+
+use crate::profiler::state::{ProgramState, RESET_CODE, StackFrame};
+
+pub struct Recording {
+    profile: Profile,
+    process: ProcessHandle,
+    threads: HashMap<u16, ThreadHandle>,
+    now: u64,
+}
+
+impl Recording {
+    pub fn new(state: &ProgramState) -> Self {
+        let symbol_file = state.symbol_file();
+
+        let name = &symbol_file.name();
+        let reference_timestamp = ReferenceTimestamp::from_millis_since_unix_epoch(0.0);
+        let interval = SamplingInterval::from_hz(20_000_000.0);
+        let mut profile = Profile::new(name, reference_timestamp, interval);
+
+        let process = profile.add_process(name, 1, Timestamp::from_nanos_since_reference(0));
+
+        let lib = profile.add_lib(symbol_file.library_info().clone());
+        profile.add_lib_mapping(process, lib, 0x00000000, 0xffffffff, 0);
+
+        let mut me = Self {
+            profile,
+            process,
+            threads: HashMap::new(),
+            now: 0,
+        };
+        me.track_elapsed_cycles(state, 0);
+        me
+    }
+
+    pub fn track_elapsed_cycles(&mut self, state: &ProgramState, cycles: u32) {
+        self.now += cycles as u64;
+        let timestamp = Timestamp::from_nanos_since_reference(self.now * 50);
+        let weight = 1;
+
+        let active_code = if let Some((code, frames)) = state.current_stack() {
+            let thread = *self.threads.entry(code).or_insert_with(|| {
+                let process = self.process;
+                let tid = code as u32;
+                let start_time = Timestamp::from_nanos_since_reference(self.now * 50);
+                let is_main = code == RESET_CODE;
+                let thread = self.profile.add_thread(process, tid, start_time, is_main);
+                self.profile
+                    .set_thread_name(thread, &thread_name_for_code(code));
+                thread
+            });
+
+            let stack = self.handle_for_stack(thread, frames);
+            let cpu_delta = CpuDelta::from_nanos((self.now - cycles as u64) * 50);
+            self.profile
+                .add_sample(thread, timestamp, stack, cpu_delta, weight);
+            Some(code)
+        } else {
+            None
+        };
+        for (code, thread) in &self.threads {
+            if active_code == Some(*code) {
+                continue;
+            }
+            self.profile
+                .add_sample_same_stack_zero_cpu(*thread, timestamp, weight);
+        }
+    }
+
+    pub fn finish(self) -> Vec<u8> {
+        serde_json::to_vec(&self.profile).expect("could not serialize profile")
+    }
+
+    fn handle_for_stack(
+        &mut self,
+        thread: ThreadHandle,
+        frames: &[StackFrame],
+    ) -> Option<StackHandle> {
+        self.profile.intern_stack_frames(
+            thread,
+            frames.iter().map(|f| FrameInfo {
+                frame: Frame::InstructionPointer(f.address as u64),
+                category_pair: CategoryHandle::OTHER.into(),
+                flags: FrameFlags::empty(),
+            }),
+        )
+    }
+}
+
+fn thread_name_for_code(code: u16) -> std::borrow::Cow<'static, str> {
+    match code {
+        RESET_CODE => "Main".into(),
+        0xffd0 => "Duplexed exception".into(),
+        0xfe40 => "VIP interrupt".into(),
+        0xfe30 => "Communication interrupt".into(),
+        0xfe20 => "Game pak interrupt".into(),
+        0xfe10 => "Timer interrupt".into(),
+        0xfe00 => "Game pad interrupt".into(),
+        0xffc0 => "Address trap".into(),
+        0xffa0..0xffc0 => format!("Trap (vector {})", code - 0xffa0).into(),
+        0xff90 => "Illegal opcode exception".into(),
+        0xff80 => "Zero division exception".into(),
+        0xff60 => "Floating-point reserved operand exception".into(),
+        0xff70 => "Floating-point invalid operation exception".into(),
+        0xff68 => "Floating-point zero division exception".into(),
+        0xff64 => "Floating-point overflow exception".into(),
+        other => format!("Unrecognized handler (0x{other:04x})").into(),
+    }
+}
diff --git a/src/profiler/state.rs b/src/profiler/state.rs
new file mode 100644
index 0000000..40bdc72
--- /dev/null
+++ b/src/profiler/state.rs
@@ -0,0 +1,104 @@
+use std::{collections::HashMap, path::PathBuf};
+
+use anyhow::{Result, bail};
+
+use crate::{emulator::SimEvent, profiler::symbols::SymbolFile};
+
+pub struct ProgramState {
+    symbol_file: SymbolFile,
+    call_stacks: HashMap<u16, Vec<StackFrame>>,
+    context_stack: Vec<u16>,
+}
+
+pub struct StackFrame {
+    pub address: u32,
+}
+
+pub const RESET_CODE: u16 = 0xfff0;
+impl ProgramState {
+    pub async fn new(file_path: PathBuf) -> Result<Self> {
+        let symbol_file = SymbolFile::load(&file_path).await?;
+        let mut call_stacks = HashMap::new();
+        call_stacks.insert(
+            RESET_CODE,
+            vec![StackFrame {
+                address: 0xfffffff0,
+            }],
+        );
+        Ok(Self {
+            symbol_file,
+            call_stacks,
+            context_stack: vec![RESET_CODE],
+        })
+    }
+
+    pub fn symbol_file(&self) -> &SymbolFile {
+        &self.symbol_file
+    }
+
+    pub fn current_stack(&self) -> Option<(u16, &[StackFrame])> {
+        let code = self.context_stack.last()?;
+        let call_stack = self.call_stacks.get(code)?;
+        Some((*code, call_stack))
+    }
+
+    pub fn track_event(&mut self, event: SimEvent) -> Result<()> {
+        match event {
+            SimEvent::Call(address) => {
+                let Some(code) = self.context_stack.last() else {
+                    bail!("How did we call anything when we're halted?");
+                };
+                let Some(stack) = self.call_stacks.get_mut(code) else {
+                    bail!("missing stack {code:04x}");
+                };
+                stack.push(StackFrame { address });
+            }
+            SimEvent::Return => {
+                let Some(code) = self.context_stack.last() else {
+                    bail!("how did we return when we're halted?");
+                };
+                let Some(stack) = self.call_stacks.get_mut(code) else {
+                    bail!("missing stack {code:04x}");
+                };
+                if stack.pop().is_none() {
+                    bail!("returned from {code:04x} but stack was empty");
+                }
+                if stack.is_empty() {
+                    bail!("returned to oblivion");
+                }
+            }
+            SimEvent::Halt => {
+                let Some(RESET_CODE) = self.context_stack.pop() else {
+                    bail!("halted when not in an interrupt");
+                };
+            }
+            SimEvent::Interrupt(code, address) => {
+                // if the CPU was halted before, wake it up now
+                if self.context_stack.is_empty() {
+                    self.context_stack.push(RESET_CODE);
+                }
+
+                self.context_stack.push(code);
+                if self
+                    .call_stacks
+                    .insert(code, vec![StackFrame { address }])
+                    .is_some()
+                {
+                    bail!("{code:04x} fired twice");
+                }
+            }
+            SimEvent::Reti => {
+                let Some(code) = self.context_stack.pop() else {
+                    bail!("RETI when halted");
+                };
+                if code == RESET_CODE {
+                    bail!("RETI when not in interrupt");
+                }
+                if self.call_stacks.remove(&code).is_none() {
+                    bail!("{code:04x} popped but never called");
+                }
+            }
+        }
+        Ok(())
+    }
+}
diff --git a/src/profiler/symbols.rs b/src/profiler/symbols.rs
new file mode 100644
index 0000000..fd84211
--- /dev/null
+++ b/src/profiler/symbols.rs
@@ -0,0 +1,67 @@
+use std::{path::Path, sync::Arc};
+
+use anyhow::Result;
+use fxprof_processed_profile::{LibraryInfo, Symbol, SymbolTable};
+use wholesym::{SymbolManager, samply_symbols::demangle_any};
+
+pub struct SymbolFile {
+    library_info: LibraryInfo,
+}
+
+impl SymbolFile {
+    pub async fn load(file_path: &Path) -> Result<Self> {
+        let normalized = normpath::PathExt::normalize(file_path)?;
+        let library_info =
+            SymbolManager::library_info_for_binary_at_path(normalized.as_path(), None).await?;
+
+        let symbol_manager = SymbolManager::with_config(Default::default());
+        let symbol_map = symbol_manager
+            .load_symbol_map_for_binary_at_path(normalized.as_path(), None)
+            .await?;
+
+        let name = library_info
+            .name
+            .or_else(|| {
+                normalized
+                    .file_name()
+                    .map(|n| n.to_string_lossy().into_owned())
+            })
+            .unwrap_or("game".to_string());
+        let debug_name = library_info.debug_name.unwrap_or_else(|| name.clone());
+        let path = library_info
+            .path
+            .unwrap_or_else(|| normalized.into_os_string().to_string_lossy().into_owned());
+        let debug_path = library_info.debug_path.unwrap_or_else(|| path.clone());
+        let debug_id = library_info.debug_id.unwrap_or_default();
+        let code_id = library_info.code_id.map(|id| id.to_string());
+        let arch = library_info.arch;
+        let symbols = symbol_map
+            .iter_symbols()
+            .map(|(address, name)| Symbol {
+                address: address + 0x07000000,
+                size: None,
+                name: demangle_any(&name),
+            })
+            .collect();
+        Ok(Self {
+            library_info: LibraryInfo {
+                name,
+                debug_name,
+                path,
+                debug_path,
+                debug_id,
+                code_id,
+                arch,
+                symbol_table: Some(Arc::new(SymbolTable::new(symbols))),
+            },
+        })
+    }
+
+    pub fn name(&self) -> &str {
+        &self.library_info.name
+    }
+
+    pub fn library_info(&self) -> &LibraryInfo {
+        &self.library_info
+    }
+}