Use Smol

[NoahR02]

Experiment: Use Smol to reduce heap allocations

Two different scenarios were measured for the tour example:

1. The memory usage on the first render
2. The memory usage n frames later (this should be about the same across frames)

Three different scenarios were measured for the 10k rows example:

1. The memory usage on the first render
2. The memory usage n frames later (this should be about the same across frames)
3. The memory usage after generating 10k rows

Usability (as a user):

SmolString is invisible to the user in the view due to impl Into being used and the experience is better than before. In update however the usage is slightly worse when getting a target's id and storing it because you have to call .into().

Results (Summary):

Tour Measurements

TOUR EXAMPLE	STARTING FRAME	N FRAMES LATER
Without Smol	allocations: 2991, bytes allocated: 1182586	allocations: 1903, bytes allocated: 818369
With Smol	allocations: 2935, bytes allocated: 1181426	allocations: 1848, bytes allocated: 817833
Memory Saved Diff (bytes)	1160 bytes and 167.04 KB across 144 frames	536 bytes and 77.184 KB across 144 frames

10k Rows Measurements

10k Rows Example	STARTING FRAME	N FRAMES LATER	10K ROWS CLICKED AND SHOWING
Without Smol	allocations: 2051, bytes allocated: 570760	allocations: 1338, bytes allocated: 392832	allocations: 751489, bytes allocated: 345547457
With Smol	allocations: 2022, bytes allocated: 570357	allocations: 1309, bytes allocated: 392429	allocations: 661651, bytes allocated: 344849956
Memory Saved Diff (bytes)	403 bytes and 58.032 KB across 144 frames	403 bytes and 58.032 KB across 144 frames	697501 bytes and 100.440144 MB across 144 frames

How to Measure:

https://github.com/neoeinstein/stats_alloc

Clone down craft with the smol changes in one directory and then clone it down without the changes in another directory and then for each directory: save the following to a patch file and git apply the patch file at the root:

diff --git a/Cargo.lock b/Cargo.lock
index 8c544e3..505ebe6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -823,6 +823,7 @@ dependencies = [
  "rustc-hash 2.1.1",
  "smallvec",
  "smol_str 0.3.2",
+ "stats_alloc",
  "syntect",
  "taffy",
  "tinyvg-rs",
@@ -3705,6 +3706,12 @@ version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
 
+[[package]]
+name = "stats_alloc"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c0e04424e733e69714ca1bbb9204c1a57f09f5493439520f9f68c132ad25eec"
+
 [[package]]
 name = "strict-num"
 version = "0.1.1"
diff --git a/crates/craft_core/Cargo.toml b/crates/craft_core/Cargo.toml
index 06a39d2..f193422 100644
--- a/crates/craft_core/Cargo.toml
+++ b/crates/craft_core/Cargo.toml
@@ -30,6 +30,7 @@ default = ["clipboard", "accesskit"]
 [dependencies]
 craft_logging = { path = "../craft_logger", version = "0.1.0" }
 
+stats_alloc = "0.1.10"
 smol_str = "0.3.2"
 
 [dependencies.cfg-if]
diff --git a/crates/craft_core/src/app.rs b/crates/craft_core/src/app.rs
index 85d5491..4329c4d 100644
--- a/crates/craft_core/src/app.rs
+++ b/crates/craft_core/src/app.rs
@@ -59,6 +59,15 @@ use craft_resource_manager::resource_type::ResourceType;
 use crate::animations::animation::{AnimationFlags};
 use crate::events::update_queue_entry::UpdateQueueEntry;
 
+extern crate stats_alloc;
+
+use stats_alloc::{StatsAlloc, Region, INSTRUMENTED_SYSTEM};
+use std::alloc::System;
+use std::process;
+
+#[global_allocator]
+static GLOBAL: &StatsAlloc<System> = &INSTRUMENTED_SYSTEM;
+
 macro_rules! get_tree {
         ($self:expr, $is_dev_tree:expr) => {{
             if !$is_dev_tree {
@@ -308,6 +317,8 @@ impl App {
     }
 
     fn on_request_redraw_internal(&mut self) {
+        let reg = Region::new(&GLOBAL);
+
         if self.window.is_none() {
             return;
         }
@@ -414,6 +425,8 @@ impl App {
         }
 
         self.view_introspection();
+        println!("Per-frame Allocations: {:#?}", reg.change());
+        // process::exit(0);
     }
 
     pub fn on_pointer_scroll(&mut self, pointer_scroll_update: PointerScrollUpdate) {

Results:

10k rows (WITHOUT Smol):

STARTING FRAME:

Per-frame Allocations: Stats {

  allocations: 2051,

  deallocations: 1207,

  reallocations: 493,

  bytes_allocated: 570760,

  bytes_deallocated: 339710,

  bytes_reallocated: 121657,

}

N FRAMES LATER:

Per-frame Allocations: Stats {

  allocations: 1338,

  deallocations: 1336,

  reallocations: 206,

  bytes_allocated: 392832,

  bytes_deallocated: 392272,

  bytes_reallocated: 71448,

}

10K ROWS CLICKED AND SHOWING:

Per-frame Allocations: Stats {

  allocations: 751489,

  deallocations: 751487,

  reallocations: 60762,

  bytes_allocated: 345547457,

  bytes_deallocated: 345546897,

  bytes_reallocated: 119599883,

}

---

10k rows (WITH Smol):

STARTING FRAME:

Per-frame Allocations: Stats {

  allocations: 2022,

  deallocations: 1206,

  reallocations: 493,

  bytes_allocated: 570357,

  bytes_deallocated: 339618,

  bytes_reallocated: 121657,

}

N FRAMES LATER:

Per-frame Allocations: Stats {

  allocations: 1309,

  deallocations: 1307,

  reallocations: 206,

  bytes_allocated: 392429,

  bytes_deallocated: 391869,

  bytes_reallocated: 71448,

}

10K ROWS CLICKED AND SHOWING:

Per-frame Allocations: Stats {

  allocations: 661651,

  deallocations: 661649,

  reallocations: 60762,

  bytes_allocated: 344849956,

  bytes_deallocated: 344849396,

  bytes_reallocated: 119599663,

}

---

Tour (WITHOUT Smol):

STARTING FRAME:

Per-frame Allocations: Stats {

  allocations: 2991,

  deallocations: 1715,

  reallocations: 963,

  bytes_allocated: 1182586,

  bytes_deallocated: 707643,

  bytes_reallocated: 407916,

}

N FRAMES LATER:

Per-frame Allocations: Stats {

  allocations: 1903,

  deallocations: 1901,

  reallocations: 484,

  bytes_allocated: 818369,

  bytes_deallocated: 817809,

  bytes_reallocated: 325752,

}

---

Tour (WITH Smol):

STARTING FRAME:

Per-frame Allocations: Stats {

  allocations: 2935,

  deallocations: 1714,

  reallocations: 963,

  bytes_allocated: 1181426,

  bytes_deallocated: 707560,

  bytes_reallocated: 407916,

}

N FRAMES LATER:

Per-frame Allocations: Stats {

  allocations: 1848,

  deallocations: 1846,

  reallocations: 484,

  bytes_allocated: 817833,

  bytes_deallocated: 817273,

  bytes_reallocated: 325752,

}