Reduce the size of events by using a u64 instead of Instant

Part of #58372

Author: wesleywiser

src/librustc/util/profiling.rs

@@ -4,7 +4,7 @@ use std::io::{BufWriter, Write};
 use std::mem;
 use std::process;
 use std::thread::ThreadId;
-use std::time::Instant;
+use std::time::{Duration, Instant, SystemTime};
 
 use crate::session::config::Options;
 
@@ -21,20 +21,20 @@ pub enum ProfileCategory {
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub enum ProfilerEvent {
- QueryStart { query_name: &'static str, category: ProfileCategory, time: Instant },
- QueryEnd { query_name: &'static str, category: ProfileCategory, time: Instant },
- GenericActivityStart { category: ProfileCategory, time: Instant },
- GenericActivityEnd { category: ProfileCategory, time: Instant },
- IncrementalLoadResultStart { query_name: &'static str, time: Instant },
- IncrementalLoadResultEnd { query_name: &'static str, time: Instant },
- QueryCacheHit { query_name: &'static str, category: ProfileCategory, time: Instant },
- QueryCount { query_name: &'static str, category: ProfileCategory, count: usize, time: Instant },
- QueryBlockedStart { query_name: &'static str, category: ProfileCategory, time: Instant },
- QueryBlockedEnd { query_name: &'static str, category: ProfileCategory, time: Instant },
+ QueryStart { query_name: &'static str, category: ProfileCategory, time: u64 },
+ QueryEnd { query_name: &'static str, category: ProfileCategory, time: u64 },
+ GenericActivityStart { category: ProfileCategory, time: u64 },
+ GenericActivityEnd { category: ProfileCategory, time: u64 },
+ IncrementalLoadResultStart { query_name: &'static str, time: u64 },
+ IncrementalLoadResultEnd { query_name: &'static str, time: u64 },
+ QueryCacheHit { query_name: &'static str, category: ProfileCategory, time: u64 },
+ QueryCount { query_name: &'static str, category: ProfileCategory, count: usize, time: u64 },
+ QueryBlockedStart { query_name: &'static str, category: ProfileCategory, time: u64 },
+ QueryBlockedEnd { query_name: &'static str, category: ProfileCategory, time: u64 },
 }
 
 impl ProfilerEvent {
- fn timestamp(&self) -> Instant {
+ fn timestamp(&self) -> u64 {
  use self::ProfilerEvent::*;
 
  match self {
@@ -58,32 +58,34 @@ fn thread_id_to_u64(tid: ThreadId) -> u64 {
 
 pub struct SelfProfiler {
  events: HashMap<ThreadId, Vec<ProfilerEvent>>,
+ start_time: SystemTime,
+ start_instant: Instant,
 }
 
 impl SelfProfiler {
  pub fn new() -> SelfProfiler {
- let mut profiler = SelfProfiler {
+ let profiler = SelfProfiler {
  events: HashMap::new(),
+ start_time: SystemTime::now(),
+ start_instant: Instant::now(),
  };
 
- profiler.start_activity(ProfileCategory::Other);
-
  profiler
  }
 
  #[inline]
  pub fn start_activity(&mut self, category: ProfileCategory) {
  self.record(ProfilerEvent::GenericActivityStart {
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
  #[inline]
  pub fn end_activity(&mut self, category: ProfileCategory) {
  self.record(ProfilerEvent::GenericActivityEnd {
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -98,7 +100,7 @@ impl SelfProfiler {
  query_name,
  category,
  count,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -107,7 +109,7 @@ impl SelfProfiler {
  self.record(ProfilerEvent::QueryCacheHit {
  query_name,
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -116,7 +118,7 @@ impl SelfProfiler {
  self.record(ProfilerEvent::QueryStart {
  query_name,
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  });
  }
 
@@ -125,23 +127,23 @@ impl SelfProfiler {
  self.record(ProfilerEvent::QueryEnd {
  query_name,
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
  #[inline]
  pub fn incremental_load_result_start(&mut self, query_name: &'static str) {
  self.record(ProfilerEvent::IncrementalLoadResultStart {
  query_name,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
  #[inline]
  pub fn incremental_load_result_end(&mut self, query_name: &'static str) {
  self.record(ProfilerEvent::IncrementalLoadResultEnd {
  query_name,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -150,7 +152,7 @@ impl SelfProfiler {
  self.record(ProfilerEvent::QueryBlockedStart {
  query_name,
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -159,7 +161,7 @@ impl SelfProfiler {
  self.record(ProfilerEvent::QueryBlockedEnd {
  query_name,
  category,
- time: Instant::now(),
+ time: self.get_time_from_start(),
  })
  }
 
@@ -171,19 +173,15 @@ impl SelfProfiler {
  events.push(event);
  }
 
+ #[inline]
+ fn get_time_from_start(&self) -> u64 {
+ let duration = Instant::now() - self.start_instant;
+ duration.as_nanos() as u64
+ }
+
  pub fn dump_raw_events(&self, opts: &Options) {
  use self::ProfilerEvent::*;
 
- //find the earliest Instant to use as t=0
- //when serializing the events, we'll calculate a Duration
- //using (instant - min_instant)
- let min_instant =
- self.events
- .iter()
- .map(|(_, values)| values[0].timestamp())
- .min()
- .unwrap();
-
  let pid = process::id();
 
  let filename =
@@ -229,8 +227,10 @@ impl SelfProfiler {
  }
 
  let (secs, nanos) = {
- let duration = event.timestamp() - min_instant;
- (duration.as_secs(), duration.subsec_nanos())
+ let time = self.start_time + Duration::from_nanos(event.timestamp());
+ let time_since_unix =
+ time.duration_since(SystemTime::UNIX_EPOCH).unwrap_or_default();
+ (time_since_unix.as_secs(), time_since_unix.subsec_nanos())
  };
 
  match event {