From ce8400bbfd8786003a112633992a3ec2b003859b Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Mon, 9 Aug 2021 18:56:19 +0300
Subject: [PATCH] internal: drop latest requests tracking

From the dawn of time, when dinosaurs roamed the and we didn't have
hierarchical profiling, there was the `latest_requests` infra we used to
track the time of ten last requests.

Today, no one is actually using it and, what's more, it itself became
pretty useless -- LSP grew way more chatty, and 10 requests don't really
paint any kind of picture.

Personally, it's been years since I last looked at latest requests in
the status output.

So, let's remove a tiny bit of state from the big ball of complexity
that is `GlobalState` and `main_loop`!
---
 crates/rust-analyzer/src/global_state.rs    | 10 +-----
 crates/rust-analyzer/src/handlers.rs        |  6 ----
 crates/rust-analyzer/src/lib.rs             |  1 -
 crates/rust-analyzer/src/request_metrics.rs | 37 ---------------------
 4 files changed, 1 insertion(+), 53 deletions(-)
 delete mode 100644 crates/rust-analyzer/src/request_metrics.rs

diff --git a/crates/rust-analyzer/src/global_state.rs b/crates/rust-analyzer/src/global_state.rs
index b21fff7071..a7ebbcd28b 100644
--- a/crates/rust-analyzer/src/global_state.rs
+++ b/crates/rust-analyzer/src/global_state.rs
@@ -27,7 +27,6 @@ use crate::{
     mem_docs::MemDocs,
     op_queue::OpQueue,
     reload::SourceRootConfig,
-    request_metrics::{LatestRequests, RequestMetrics},
     thread_pool::TaskPool,
     to_proto::url_from_abs_path,
     Result,
@@ -105,8 +104,6 @@ pub(crate) struct GlobalState {
         OpQueue<(Arc<Vec<ProjectWorkspace>>, Vec<anyhow::Result<WorkspaceBuildScripts>>)>,
 
     pub(crate) prime_caches_queue: OpQueue<()>,
-
-    latest_requests: Arc<RwLock<LatestRequests>>,
 }
 
 /// An immutable snapshot of the world's state at a point in time.
@@ -114,7 +111,6 @@ pub(crate) struct GlobalStateSnapshot {
     pub(crate) config: Arc<Config>,
     pub(crate) analysis: Analysis,
     pub(crate) check_fixes: CheckFixes,
-    pub(crate) latest_requests: Arc<RwLock<LatestRequests>>,
     mem_docs: MemDocs,
     pub(crate) semantic_tokens_cache: Arc<Mutex<FxHashMap<Url, SemanticTokens>>>,
     vfs: Arc<RwLock<(vfs::Vfs, FxHashMap<FileId, LineEndings>)>>,
@@ -169,7 +165,6 @@ impl GlobalState {
             prime_caches_queue: OpQueue::default(),
 
             fetch_build_data_queue: OpQueue::default(),
-            latest_requests: Default::default(),
         };
         // Apply any required database inputs from the config.
         this.update_configuration(config);
@@ -230,7 +225,6 @@ impl GlobalState {
             workspaces: Arc::clone(&self.workspaces),
             analysis: self.analysis_host.analysis(),
             vfs: Arc::clone(&self.vfs),
-            latest_requests: Arc::clone(&self.latest_requests),
             check_fixes: Arc::clone(&self.diagnostics.check_fixes),
             mem_docs: self.mem_docs.clone(),
             semantic_tokens_cache: Arc::clone(&self.semantic_tokens_cache),
@@ -270,9 +264,7 @@ impl GlobalState {
     pub(crate) fn respond(&mut self, response: lsp_server::Response) {
         if let Some((method, start)) = self.req_queue.incoming.complete(response.id.clone()) {
             let duration = start.elapsed();
-            log::info!("handled req#{} in {:?}", response.id, duration);
-            let metrics = RequestMetrics { id: response.id.clone(), method, duration };
-            self.latest_requests.write().record(metrics);
+            log::info!("handled {} - ({}) in {:0.2?}", method, response.id, duration);
             self.send(response.into());
         }
     }
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index c9a25e086a..460271a269 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -79,12 +79,6 @@ pub(crate) fn handle_analyzer_status(
             .status(file_id)
             .unwrap_or_else(|_| "Analysis retrieval was cancelled".to_owned()),
     );
-    format_to!(buf, "\n\nRequests:\n");
-    let requests = snap.latest_requests.read();
-    for (is_last, r) in requests.iter() {
-        let mark = if is_last { "*" } else { " " };
-        format_to!(buf, "{}{:4} {:<36}{}ms\n", mark, r.id, r.method, r.duration.as_millis());
-    }
     Ok(buf)
 }
 
diff --git a/crates/rust-analyzer/src/lib.rs b/crates/rust-analyzer/src/lib.rs
index a5997d69d9..c8c996f0da 100644
--- a/crates/rust-analyzer/src/lib.rs
+++ b/crates/rust-analyzer/src/lib.rs
@@ -30,7 +30,6 @@ mod semantic_tokens;
 mod markdown;
 mod diagnostics;
 mod line_index;
-mod request_metrics;
 mod lsp_utils;
 mod thread_pool;
 mod mem_docs;
diff --git a/crates/rust-analyzer/src/request_metrics.rs b/crates/rust-analyzer/src/request_metrics.rs
deleted file mode 100644
index b1019e2d6f..0000000000
--- a/crates/rust-analyzer/src/request_metrics.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-//! Records stats about requests
-use std::time::Duration;
-
-use lsp_server::RequestId;
-
-#[derive(Debug)]
-pub(crate) struct RequestMetrics {
-    pub(crate) id: RequestId,
-    pub(crate) method: String,
-    pub(crate) duration: Duration,
-}
-
-const N_COMPLETED_REQUESTS: usize = 10;
-
-#[derive(Debug, Default)]
-pub(crate) struct LatestRequests {
-    // hand-rolling VecDeque here to print things in a nicer way
-    buf: [Option<RequestMetrics>; N_COMPLETED_REQUESTS],
-    idx: usize,
-}
-
-impl LatestRequests {
-    pub(crate) fn record(&mut self, request: RequestMetrics) {
-        // special case: don't track status request itself
-        if request.method == "rust-analyzer/analyzerStatus" {
-            return;
-        }
-        let idx = self.idx;
-        self.buf[idx] = Some(request);
-        self.idx = (idx + 1) % N_COMPLETED_REQUESTS;
-    }
-
-    pub(crate) fn iter(&self) -> impl Iterator<Item = (bool, &RequestMetrics)> {
-        let idx = self.idx;
-        self.buf.iter().enumerate().filter_map(move |(i, req)| Some((i == idx, req.as_ref()?)))
-    }
-}