1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167

use crate::file_header::{write_file_header, FILE_MAGIC_EVENT_STREAM, FILE_MAGIC_TOP_LEVEL};
use crate::raw_event::RawEvent;
use crate::serialization::{PageTag, SerializationSink, SerializationSinkBuilder};
use crate::stringtable::{SerializableString, StringId, StringTableBuilder};
use crate::{event_id::EventId, file_header::FILE_EXTENSION};
use std::error::Error;
use std::fs;
use std::path::Path;
use std::sync::Arc;
use std::time::Instant;

pub struct Profiler {
    event_sink: Arc<SerializationSink>,
    string_table: StringTableBuilder,
    start_time: Instant,
}

impl Profiler {
    pub fn new<P: AsRef<Path>>(path_stem: P) -> Result<Profiler, Box<dyn Error + Send + Sync>> {
        let path = path_stem.as_ref().with_extension(FILE_EXTENSION);

        fs::create_dir_all(path.parent().unwrap())?;
        let mut file = fs::File::create(path)?;

        // The first thing in the file must be the top-level file header.
        write_file_header(&mut file, FILE_MAGIC_TOP_LEVEL)?;

        let sink_builder = SerializationSinkBuilder::new_from_file(file)?;
        let event_sink = Arc::new(sink_builder.new_sink(PageTag::Events));

        // The first thing in every stream we generate must be the stream header.
        write_file_header(&mut event_sink.as_std_write(), FILE_MAGIC_EVENT_STREAM)?;

        let string_table = StringTableBuilder::new(
            Arc::new(sink_builder.new_sink(PageTag::StringData)),
            Arc::new(sink_builder.new_sink(PageTag::StringIndex)),
        )?;

        let profiler = Profiler {
            event_sink,
            string_table,
            start_time: Instant::now(),
        };

        let mut args = String::new();
        for arg in std::env::args() {
            args.push_str(&arg.escape_default().to_string());
            args.push(' ');
        }

        profiler.string_table.alloc_metadata(&*format!(
            r#"{{ "start_time": {}, "process_id": {}, "cmd": "{}" }}"#,
            std::time::SystemTime::now()
                .duration_since(std::time::UNIX_EPOCH)
                .unwrap()
                .as_nanos(),
            std::process::id(),
            args,
        ));

        Ok(profiler)
    }

    #[inline(always)]
    pub fn map_virtual_to_concrete_string(&self, virtual_id: StringId, concrete_id: StringId) {
        self.string_table
            .map_virtual_to_concrete_string(virtual_id, concrete_id);
    }

    #[inline(always)]
    pub fn bulk_map_virtual_to_single_concrete_string<I>(
        &self,
        virtual_ids: I,
        concrete_id: StringId,
    ) where
        I: Iterator<Item = StringId> + ExactSizeIterator,
    {
        self.string_table
            .bulk_map_virtual_to_single_concrete_string(virtual_ids, concrete_id);
    }

    #[inline(always)]
    pub fn alloc_string<STR: SerializableString + ?Sized>(&self, s: &STR) -> StringId {
        self.string_table.alloc(s)
    }

    /// Records an event with the given parameters. The event time is computed
    /// automatically.
    pub fn record_instant_event(&self, event_kind: StringId, event_id: EventId, thread_id: u32) {
        let raw_event =
            RawEvent::new_instant(event_kind, event_id, thread_id, self.nanos_since_start());

        self.record_raw_event(&raw_event);
    }

    /// Creates a "start" event and returns a `TimingGuard` that will create
    /// the corresponding "end" event when it is dropped.
    #[inline]
    pub fn start_recording_interval_event<'a>(
        &'a self,
        event_kind: StringId,
        event_id: EventId,
        thread_id: u32,
    ) -> TimingGuard<'a> {
        TimingGuard {
            profiler: self,
            event_id,
            event_kind,
            thread_id,
            start_ns: self.nanos_since_start(),
        }
    }

    fn record_raw_event(&self, raw_event: &RawEvent) {
        self.event_sink
            .write_atomic(std::mem::size_of::<RawEvent>(), |bytes| {
                raw_event.serialize(bytes);
            });
    }

    fn nanos_since_start(&self) -> u64 {
        self.start_time.elapsed().as_nanos() as _
    }
}

/// When dropped, this `TimingGuard` will record an "end" event in the
/// `Profiler` it was created by.
#[must_use]
pub struct TimingGuard<'a> {
    profiler: &'a Profiler,
    event_id: EventId,
    event_kind: StringId,
    thread_id: u32,
    start_ns: u64,
}

impl<'a> Drop for TimingGuard<'a> {
    #[inline]
    fn drop(&mut self) {
        let raw_event = RawEvent::new_interval(
            self.event_kind,
            self.event_id,
            self.thread_id,
            self.start_ns,
            self.profiler.nanos_since_start(),
        );

        self.profiler.record_raw_event(&raw_event);
    }
}

impl<'a> TimingGuard<'a> {
    /// This method set a new `event_id` right before actually recording the
    /// event.
    #[inline]
    pub fn finish_with_override_event_id(mut self, event_id: EventId) {
        self.event_id = event_id;
        // Let's be explicit about it: Dropping the guard will record the event.
        drop(self)
    }
}

// Make sure that `Profiler` can be used in a multithreaded context
fn _assert_bounds() {
    assert_bounds_inner(&Profiler::new(""));
    fn assert_bounds_inner<S: Sized + Send + Sync + 'static>(_: &S) {}
}