Removed more allocations + other optimizations

The most noisy change is that all public APIs are now marked as inline,
allowing the optimizer to see through many APIs. This produces nearly
identical results to enabling LTO.

The next optimization was to change read_buffered_bytes to reuse a
scratch buffer. This allows buffered reads to share a single allocation,
preventing many tiny allocations when reading things like bytes/strings
from a reader.

The final big optimization was to make SymbolMap store its list of
'ephemeral' strings in a single String, only storing the offsets. This
further reduced the number of allocations deserializing data required.

Some minor optimizations to how headers are encoded to optimize for the
most common paths also have been made.

All said, these changes account for ~10% improvement in the logs
benchmark on average, depending on the data set.

Cargo.toml

@@ -1,5 +1,6 @@
 [workspace]
-members = ["xtask", "pot"]
+members = ["xtask", "pot", "benchmarks"]
 
 [profile.bench]
 # debug = true
+lto = true

benchmarks/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "benchmarks"
+version = "0.0.0"
+edition = "2021"
+publish = false
+
+[dependencies]
+serde = { version = "1.0.136", features = ["derive"] }
+pot = { path = "../pot" }
+rand = "0.8.4"
+fake = "2.4.3"
+chrono = { version = "0.4.19", features = ["serde"] }
+anyhow = "1.0.53"
+cli-table = "0.4.6"
+thousands = "0.2.0"
+ciborium = "0.2.0"
+bincode = "1.3.3"
+rmp-serde = "1.1.0"
+criterion = { version = "0.5", features = ["html_reports"] }
+
+
+[[bench]]
+name = "benchmarks"
+harness = false

pot/benches/benchmarks.rs → benchmarks/benches/benchmarks.rs

@@ -2,6 +2,7 @@
 //!
 //! Proper benchmarks will be coming.
 
+use std::env;
 use std::fmt::Display;
 
 use chrono::{DateTime, Utc};
@@ -10,7 +11,8 @@ use fake::faker::filesystem::en::FilePath;
 use fake::faker::internet::en::Username;
 use fake::faker::lorem::en::Sentence;
 use fake::Fake;
-use rand::{thread_rng, Rng};
+use rand::rngs::StdRng;
+use rand::{thread_rng, Rng, SeedableRng};
 use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize, Debug, PartialEq)]
@@ -107,8 +109,36 @@ fn bench_logs(c: &mut Criterion) {
     let mut logs = LogArchive {
         entries: Vec::with_capacity(LOG_ENTRIES),
     };
+    let random_seed = env::args().find(|arg| arg.starts_with("-s")).map_or_else(
+        || thread_rng().gen(),
+        |seed| {
+            let (_, seed) = seed.split_at(2);
+            let (upper, lower) = if seed.len() > 32 {
+                let (upper, lower) = seed.split_at(seed.len() - 32);
+                (
+                    u128::from_str_radix(upper, 16).expect("invalid hexadecimal seed"),
+                    u128::from_str_radix(lower, 16).expect("invalid hexadecimal seed"),
+                )
+            } else {
+                (
+                    0,
+                    u128::from_str_radix(seed, 16).expect("invalid hexadecimal seed"),
+                )
+            };
+            let mut seed = [0; 32];
+            seed[..16].copy_from_slice(&upper.to_be_bytes());
+            seed[16..].copy_from_slice(&lower.to_be_bytes());
+            seed
+        },
+    );
+    print!("Using random seed -s");
+    for b in random_seed {
+        print!("{b:02x}");
+    }
+    println!();
+    let mut rng = StdRng::from_seed(random_seed);
     for _ in 0..LOG_ENTRIES {
-        logs.entries.push(Log::generate(&mut thread_rng()));
+        logs.entries.push(Log::generate(&mut rng));
     }
 
     let mut serialize_group = c.benchmark_group("logs/serialize");

pot/Cargo.toml

@@ -21,20 +21,5 @@ half = "2.2.1"
 [dev-dependencies]
 tracing-subscriber = "0.3.8"
 tracing = "0.1.30"
-rand = "0.8.4"
-fake = "2.4.3"
-chrono = { version = "0.4.19", features = ["serde"] }
-anyhow = "1.0.53"
-cli-table = "0.4.6"
-thousands = "0.2.0"
-ciborium = "0.2.0"
-bincode = "1.3.3"
-rmp-serde = "1.1.0"
-criterion = { version = "0.5", features = ["html_reports"] }
 serde_bytes = "0.11.5"
-serde_json = "1.0.78"
 approx = "0.5.1"
-
-[[bench]]
-name = "benchmarks"
-harness = false