diff --git a/Cargo.lock b/Cargo.lock
index d82916f921..87115efff5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6586,6 +6586,8 @@ dependencies = [
  "chrono",
  "clap",
  "crc32c",
+ "criterion",
+ "desim",
  "env_logger",
  "fail",
  "futures",
@@ -6633,9 +6635,11 @@ dependencies = [
  "tokio-util",
  "tonic",
  "tracing",
+ "tracing-subscriber",
  "url",
  "utils",
  "wal_decoder",
+ "walproposer",
  "workspace_hack",
 ]
 
diff --git a/libs/sk_ps_discovery/Cargo.toml b/libs/sk_ps_discovery/Cargo.toml
index 8c761b025e..9022d176c1 100644
--- a/libs/sk_ps_discovery/Cargo.toml
+++ b/libs/sk_ps_discovery/Cargo.toml
@@ -67,3 +67,15 @@ utils.workspace = true
 wal_decoder.workspace = true
 env_logger.workspace = true
 
+[dev-dependencies]
+criterion.workspace = true
+itertools.workspace = true
+walproposer.workspace = true
+rand.workspace = true
+desim.workspace = true
+tracing.workspace = true
+tracing-subscriber = { workspace = true, features = ["json"] }
+
+[[bench]]
+name = "bench"
+harness = false
diff --git a/libs/sk_ps_discovery/benches/bench.rs b/libs/sk_ps_discovery/benches/bench.rs
new file mode 100644
index 0000000000..4c7b4a486d
--- /dev/null
+++ b/libs/sk_ps_discovery/benches/bench.rs
@@ -0,0 +1,86 @@
+//! WAL ingestion benchmarks.
+
+use std::time::Instant;
+
+use criterion::Criterion;
+use hex::FromHex;
+use sk_ps_discovery::{
+    AttachmentUpdate, RemoteConsistentLsnAdv, TenantShardAttachmentId, TimelineAttachmentId,
+};
+use utils::{
+    generation::Generation,
+    id::{TenantId, TenantTimelineId, TimelineId},
+    shard::ShardIndex,
+};
+
+/// Use jemalloc and enable profiling, to mirror bin/safekeeper.rs.
+#[global_allocator]
+static GLOBAL: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
+
+#[allow(non_upper_case_globals)]
+#[unsafe(export_name = "malloc_conf")]
+pub static malloc_conf: &[u8] = b"prof:true,prof_active:true,lg_prof_sample:21\0";
+
+// Register benchmarks with Criterion.
+criterion_group!(
+    name = benches;
+    config = Criterion::default().with_profiler(PProfProfiler::new(100, Output::Flamegraph(None)));
+    targets = bench_simple,
+);
+criterion_main!(benches);
+
+fn bench_simple(c: &mut Criterion) {
+    let mut g = c.benchmark_group("simple");
+
+    // setup
+    let mut world = sk_ps_discovery::World::default();
+
+    // Simplified view: lots of tenants with one timeline each
+    let n_tenants = 400_000;
+    for t in 1..=n_tenants {
+        let ps_id = NodeId(23);
+        let tenant_id = TenantId::from_hex(format!("{t:x}")).unwrap();
+        let timeline_id = TimelineId::generate();
+        let tenant_shard_attachment_id = TenantShardAttachmentId {
+            tenant_id,
+            shard_id: ShardIndex::unsharded(),
+            generation: Generation(0),
+        };
+        let timeline_attachment = TimelineAttachmentId {
+            tenant_shard_attachment_id,
+            timeline_id,
+        };
+        world.update_attachment(AttachmentUpdate {
+            tenant_shard_attachment_id,
+            action: sk_ps_discovery::AttachmentUpdateAction::Attach { ps_id },
+        });
+        world.handle_remote_consistent_lsn_advertisement(RemoteConsistentLsnAdv {
+            remote_consistent_lsn: Lsn(23),
+            attachment: timeline_attachment,
+        });
+        world.handle_commit_lsn_advancement(
+            TenantTimelineId {
+                tenant_id,
+                timeline_id,
+            },
+            Lsn(42),
+        );
+    }
+
+    // setup done
+    let world = world;
+    g.bench_function("get_commit_lsn_advertisements", |bencher| {
+        bencher.iter_custom(|iters| {
+            let started = Instant::now();
+
+            for _ in 0..iters {
+                criterion::black_box(world.get_commit_lsn_advertisements());
+            }
+
+            let elapsed = started.elapsed();
+            elapsed
+        });
+    });
+
+    g.finish();
+}
diff --git a/libs/sk_ps_discovery/src/lib.rs b/libs/sk_ps_discovery/src/lib.rs
index 026331acc2..4e7359d37f 100644
--- a/libs/sk_ps_discovery/src/lib.rs
+++ b/libs/sk_ps_discovery/src/lib.rs
@@ -19,21 +19,21 @@ pub struct World {
 }
 
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
-struct TenantShardAttachmentId {
-    tenant_id: TenantId,
-    shard_id: ShardIndex,
-    generation: Generation,
+pub struct TenantShardAttachmentId {
+    pub tenant_id: TenantId,
+    pub shard_id: ShardIndex,
+    pub generation: Generation,
 }
 
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
-struct TimelineAttachmentId {
-    tenant_shard_attachment_id: TenantShardAttachmentId,
-    timeline_id: TimelineId,
+pub struct TimelineAttachmentId {
+    pub tenant_shard_attachment_id: TenantShardAttachmentId,
+    pub timeline_id: TimelineId,
 }
 
 pub struct AttachmentUpdate {
-    tenant_shard_attachment_id: TenantShardAttachmentId,
-    action: AttachmentUpdateAction,
+    pub tenant_shard_attachment_id: TenantShardAttachmentId,
+    pub action: AttachmentUpdateAction,
 }
 
 pub enum AttachmentUpdateAction {
@@ -42,8 +42,8 @@ pub enum AttachmentUpdateAction {
 }
 
 pub struct RemoteConsistentLsnAdv {
-    attachment: TimelineAttachmentId,
-    remote_consistent_lsn: Lsn,
+    pub attachment: TimelineAttachmentId,
+    pub remote_consistent_lsn: Lsn,
 }
 
 impl World {
diff --git a/safekeeper/src/timeline_manager.rs b/safekeeper/src/timeline_manager.rs
index c03e422bf6..729d3b0409 100644
--- a/safekeeper/src/timeline_manager.rs
+++ b/safekeeper/src/timeline_manager.rs
@@ -511,6 +511,7 @@ impl Manager {
             || num_computes > 0
             || state.remote_consistent_lsn < state.commit_lsn;
 
+
         // update the broker timeline set
         if self.tli_broker_active.set(is_active) {
             // write log if state has changed