uses nanos precision for timestamp when submitting metrics to influxdb

Current datapoint_info! is apparently overwriting itself when run inside
a loop. For example in
https://github.com/solana-labs/solana/blob/005d6863f/core/src/window_service.rs#L101-L107
only one of the slots will show up in influxdb.

This is apparently because of metrics code using milliseconds as the
timestamp, as mentioned here:
solana-labs#19789 (comment)

metrics/src/counter.rs

@@ -1,8 +1,13 @@
-use crate::metrics::submit_counter;
-use log::*;
-use solana_sdk::timing;
-use std::env;
-use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};
+use {
+    crate::metrics::submit_counter,
+    log::*,
+    solana_sdk::timing,
+    std::{
+        env,
+        sync::atomic::{AtomicU64, AtomicUsize, Ordering},
+        time::SystemTime,
+    },
+};
 
 const DEFAULT_LOG_RATE: usize = 1000;
 // Submit a datapoint every second by default
@@ -23,7 +28,7 @@ pub struct Counter {
 pub struct CounterPoint {
     pub name: &'static str,
     pub count: i64,
-    pub timestamp: u64,
+    pub timestamp: SystemTime,
 }
 
 impl CounterPoint {
@@ -32,7 +37,7 @@ impl CounterPoint {
         CounterPoint {
             name,
             count: 0,
-            timestamp: 0,
+            timestamp: std::time::UNIX_EPOCH,
         }
     }
 }
@@ -198,7 +203,7 @@ impl Counter {
             let counter = CounterPoint {
                 name: self.name,
                 count: counts as i64 - lastlog as i64,
-                timestamp: now,
+                timestamp: SystemTime::now(),
             };
             submit_counter(counter, level, bucket);
         }

metrics/src/datapoint.rs

@@ -1,17 +1,17 @@
-use std::fmt;
+use std::{fmt, time::SystemTime};
 
 #[derive(Clone, Debug)]
 pub struct DataPoint {
     pub name: &'static str,
-    pub timestamp: u64,
+    pub timestamp: SystemTime,
     pub fields: Vec<(&'static str, String)>,
 }
 
 impl DataPoint {
     pub fn new(name: &'static str) -> Self {
         DataPoint {
             name,
-            timestamp: solana_sdk::timing::timestamp(),
+            timestamp: SystemTime::now(),
             fields: vec![],
         }
     }

metrics/src/metrics.rs

@@ -1,20 +1,23 @@
 //! The `metrics` module enables sending measurements to an `InfluxDB` instance
 
-use crate::{counter::CounterPoint, datapoint::DataPoint};
-use gethostname::gethostname;
-use lazy_static::lazy_static;
-use log::*;
-use solana_sdk::hash::hash;
-use std::{
-    collections::HashMap,
-    convert::Into,
-    sync::{
-        mpsc::{channel, Receiver, RecvTimeoutError, Sender},
-        Arc, Barrier, Mutex, Once, RwLock,
+use {
+    crate::{counter::CounterPoint, datapoint::DataPoint},
+    gethostname::gethostname,
+    lazy_static::lazy_static,
+    log::*,
+    solana_sdk::hash::hash,
+    std::{
+        cmp,
+        collections::HashMap,
+        convert::Into,
+        env,
+        sync::{
+            mpsc::{channel, Receiver, RecvTimeoutError, Sender},
+            Arc, Barrier, Mutex, Once, RwLock,
+        },
+        thread,
+        time::{Duration, Instant, UNIX_EPOCH},
     },
-    thread,
-    time::{Duration, Instant},
-    {cmp, env},
 };
 
 type CounterMap = HashMap<(&'static str, u64), CounterPoint>;
@@ -68,7 +71,7 @@ impl InfluxDbMetricsWriter {
         );
 
         let write_url = format!(
-            "{}/write?db={}&u={}&p={}&precision=ms",
+            "{}/write?db={}&u={}&p={}&precision=n",
             &config.host, &config.db, &config.username, &config.password
         );
 
@@ -97,8 +100,9 @@ impl MetricsWriter for InfluxDbMetricsWriter {
                     ));
                     first = false;
                 }
-
-                line.push_str(&format!(" {}\n", &point.timestamp));
+                let timestamp = point.timestamp.duration_since(UNIX_EPOCH);
+                let nanos = timestamp.unwrap().as_nanos();
+                line.push_str(&format!(" {}\n", nanos));
             }
 
             let client = reqwest::blocking::Client::builder()