From f627beca8c6ae73a2eb7ed1cf0401148fe6ec1f9 Mon Sep 17 00:00:00 2001
From: Andre Guedes <andre.guedes@relational.ai>
Date: Fri, 12 Apr 2024 20:11:43 -0300
Subject: [PATCH 1/2] Limit the number of byte chunks in handle_get

---
 Cargo.lock      | 194 +++++++++++-------------------------------------
 Cargo.toml      |   2 +-
 src/crud_ops.rs |  32 ++++----
 3 files changed, 62 insertions(+), 166 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index dccbcd1..c9f8710 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -57,7 +57,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "81953c529336010edd6d8e358f886d9581267795c61b19475b71314bffa46d35"
 dependencies = [
  "concurrent-queue",
- "event-listener",
+ "event-listener 2.5.3",
  "futures-core",
 ]
 
@@ -78,11 +78,13 @@ dependencies = [
 
 [[package]]
 name = "async-lock"
-version = "2.8.0"
+version = "3.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "287272293e9d8c41773cec55e365490fe034813a2f172f502d6ddcf75b2f582b"
+checksum = "d034b430882f8381900d3fe6f0aaa3ad94f2cb4ac519b429692a1bc2dda4ae7b"
 dependencies = [
- "event-listener",
+ "event-listener 4.0.3",
+ "event-listener-strategy",
+ "pin-project-lite",
 ]
 
 [[package]]
@@ -161,49 +163,12 @@ version = "3.14.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f30e7476521f6f8af1a1c4c0b8cc94f0bee37d91763d0ca2665f299b6cd8aec"
 
-[[package]]
-name = "bytecount"
-version = "0.6.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1e5f035d16fc623ae5f74981db80a439803888314e3a555fd6f04acd51a3205"
-
 [[package]]
 name = "bytes"
 version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2bd12c1caf447e69cd4528f47f94d203fd2582878ecb9e9465484c4148a8223"
 
-[[package]]
-name = "camino"
-version = "1.1.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c59e92b5a388f549b863a7bea62612c09f24c8393560709a54558a9abdfb3b9c"
-dependencies = [
- "serde",
-]
-
-[[package]]
-name = "cargo-platform"
-version = "0.1.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e34637b3140142bdf929fb439e8aa4ebad7651ebf7b1080b3930aa16ac1459ff"
-dependencies = [
- "serde",
-]
-
-[[package]]
-name = "cargo_metadata"
-version = "0.14.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4acbb09d9ee8e23699b9634375c72795d095bf268439da88562cf9b501f181fa"
-dependencies = [
- "camino",
- "cargo-platform",
- "semver",
- "serde",
- "serde_json",
-]
-
 [[package]]
 name = "cc"
 version = "1.0.83"
@@ -384,35 +349,42 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
 [[package]]
-name = "errno"
-version = "0.3.8"
+name = "event-listener"
+version = "2.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a258e46cdc063eb8519c00b9fc845fc47bcfca4130e2f08e88665ceda8474245"
-dependencies = [
- "libc",
- "windows-sys 0.52.0",
-]
+checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
 
 [[package]]
-name = "error-chain"
-version = "0.12.4"
+name = "event-listener"
+version = "4.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2d2f06b9cac1506ece98fe3231e3cc9c4410ec3d5b1f24ae1c8946f0742cdefc"
+checksum = "67b215c49b2b248c855fb73579eb1f4f26c38ffdc12973e20e07b91d78d5646e"
 dependencies = [
- "version_check",
+ "concurrent-queue",
+ "parking",
+ "pin-project-lite",
 ]
 
 [[package]]
 name = "event-listener"
-version = "2.5.3"
+version = "5.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0206175f82b8d6bf6652ff7d71a1e27fd2e4efde587fd368662814d6ec1d9ce0"
+checksum = "6d9944b8ca13534cdfb2800775f8dd4902ff3fc75a50101466decadfdf322a24"
+dependencies = [
+ "concurrent-queue",
+ "parking",
+ "pin-project-lite",
+]
 
 [[package]]
-name = "fastrand"
-version = "2.0.1"
+name = "event-listener-strategy"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "25cbce373ec4653f1a01a31e8a5e5ec0c622dc27ff9c4e6606eefef5cbbed4a5"
+checksum = "958e4d70b6d5e81971bebec42271ec641e7ff4e170a6fa605f2b8a8b65cb97d3"
+dependencies = [
+ "event-listener 4.0.3",
+ "pin-project-lite",
+]
 
 [[package]]
 name = "flate2"
@@ -556,12 +528,6 @@ version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4271d37baee1b8c7e4b708028c57d816cf9d2434acb33a549475f78c181f6253"
 
-[[package]]
-name = "glob"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2fabcfbdc87f4758337ca535fb41a6d701b65693ce38287d856d1674551ec9b"
-
 [[package]]
 name = "h2"
 version = "0.3.26"
@@ -874,12 +840,6 @@ version = "0.5.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
 
-[[package]]
-name = "linux-raw-sys"
-version = "0.4.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4cd1a83af159aa67994778be9070f0ae1bd732942279cabb14f86f986a21456"
-
 [[package]]
 name = "lock_api"
 version = "0.4.11"
@@ -905,15 +865,6 @@ dependencies = [
  "linked-hash-map",
 ]
 
-[[package]]
-name = "mach2"
-version = "0.4.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d0d1830bcd151a6fc4aea1369af235b36c1528fe976b8ff678683c9995eade8"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "match_cfg"
 version = "0.1.0"
@@ -982,21 +933,21 @@ dependencies = [
 
 [[package]]
 name = "moka"
-version = "0.12.1"
+version = "0.12.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d8017ec3548ffe7d4cef7ac0e12b044c01164a74c0f3119420faeaf13490ad8b"
+checksum = "87bfd249f570638bfb0b4f9d258e6b8cddd2a5a7d0ed47e8bb8b176bfc0e7a17"
 dependencies = [
  "async-lock",
  "async-trait",
  "crossbeam-channel",
  "crossbeam-epoch",
  "crossbeam-utils",
+ "event-listener 5.3.0",
  "futures-util",
  "once_cell",
  "parking_lot",
  "quanta",
  "rustc_version",
- "skeptic",
  "smallvec",
  "tagptr",
  "thiserror",
@@ -1117,6 +1068,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
 
+[[package]]
+name = "parking"
+version = "2.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb813b8af86854136c6922af0598d719255ecb2179515e6e7730d468f05c9cae"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.1"
@@ -1179,26 +1136,14 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "pulldown-cmark"
-version = "0.9.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77a1a2f1f0a7ecff9c31abbe177637be0e97a0aef46cf8738ece09327985d998"
-dependencies = [
- "bitflags 1.3.2",
- "memchr",
- "unicase",
-]
-
 [[package]]
 name = "quanta"
-version = "0.11.1"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a17e662a7a8291a865152364c20c7abc5e60486ab2001e8ec10b24862de0b9ab"
+checksum = "8e5167a477619228a0b284fac2674e3c388cba90631d7b7de620e6f1fcd08da5"
 dependencies = [
  "crossbeam-utils",
  "libc",
- "mach2",
  "once_cell",
  "raw-cpuid",
  "wasi",
@@ -1263,11 +1208,11 @@ dependencies = [
 
 [[package]]
 name = "raw-cpuid"
-version = "10.7.0"
+version = "11.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c297679cb867470fa8c9f67dbba74a78d78e3e98d7cf2b08d6d71540f797332"
+checksum = "9d86a7c4638d42c44551f4791a20e687dbb4c3de1f33c43dd71e355cd429def1"
 dependencies = [
- "bitflags 1.3.2",
+ "bitflags 2.4.1",
 ]
 
 [[package]]
@@ -1407,19 +1352,6 @@ dependencies = [
  "semver",
 ]
 
-[[package]]
-name = "rustix"
-version = "0.38.28"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72e572a5e8ca657d7366229cdde4bd14c4eb5499a9573d4d366fe1b599daa316"
-dependencies = [
- "bitflags 2.4.1",
- "errno",
- "libc",
- "linux-raw-sys",
- "windows-sys 0.52.0",
-]
-
 [[package]]
 name = "rustls"
 version = "0.21.10"
@@ -1531,9 +1463,6 @@ name = "semver"
 version = "1.0.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "836fa6a3e1e547f9a2c4040802ec865b5d85f4014efe00555d7090a3dcaa1090"
-dependencies = [
- "serde",
-]
 
 [[package]]
 name = "serde"
@@ -1596,21 +1525,6 @@ dependencies = [
  "libc",
 ]
 
-[[package]]
-name = "skeptic"
-version = "0.13.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "16d23b015676c90a0f01c197bfdc786c20342c73a0afdda9025adb0bc42940a8"
-dependencies = [
- "bytecount",
- "cargo_metadata",
- "error-chain",
- "glob",
- "pulldown-cmark",
- "tempfile",
- "walkdir",
-]
-
 [[package]]
 name = "slab"
 version = "0.4.9"
@@ -1719,19 +1633,6 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
 
-[[package]]
-name = "tempfile"
-version = "3.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7ef1adac450ad7f4b3c28589471ade84f25f731a7a0fe30d71dfa9f60fd808e5"
-dependencies = [
- "cfg-if",
- "fastrand",
- "redox_syscall",
- "rustix",
- "windows-sys 0.48.0",
-]
-
 [[package]]
 name = "thiserror"
 version = "1.0.50"
@@ -1915,15 +1816,6 @@ version = "1.17.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "42ff0bf0c66b8238c6f3b578df37d0b7848e55df8577b3f74f92a69acceeb825"
 
-[[package]]
-name = "unicase"
-version = "2.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f7d2d4dafb69621809a81864c9c1b864479e1235c0dd4e199924b9742439ed89"
-dependencies = [
- "version_check",
-]
-
 [[package]]
 name = "unicode-bidi"
 version = "0.3.14"
diff --git a/Cargo.toml b/Cargo.toml
index 1b0792b..552a3f2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,7 +27,7 @@ anyhow = { version = "1", features = ["backtrace"] }
 once_cell = "1.18"
 async-channel = "1.9.0"
 crossbeam-queue = "0.3.8"
-moka = { version = "0.12.0", features = ["future"] }
+moka = { version = "0.12.6", features = ["future"] }
 url = "2.4"
 serde = "1"
 serde_json = "1"
diff --git a/src/crud_ops.rs b/src/crud_ops.rs
index 51ccdc5..e638af8 100644
--- a/src/crud_ops.rs
+++ b/src/crud_ops.rs
@@ -95,24 +95,28 @@ pub(crate) async fn handle_get(slice: &mut [u8], path: &Path, config: &Config) -
 
     // Single part Get
     let body = client.get(path).await?;
-    let mut chunks = body.into_stream().collect::<Vec<_>>().await;
-    if let Some(pos) = chunks.iter().position(|result| result.is_err()) {
-        let e = chunks.remove(pos).err().expect("already checked for error");
-        tracing::warn!("Error while fetching a chunk: {}", e);
-        return Err(e.into());
-    }
+    let mut batch_stream = body.into_stream().chunks(8);
 
     let mut received_bytes = 0;
-    for result in chunks {
-        let chunk = result.expect("checked `chunks` for errors before calling `spawn`");
-        let len = chunk.len();
+    while let Some(batch) = batch_stream.next().await {
+        for result in batch {
+            let chunk = match result {
+                Ok(c) => c,
+                Err(e) => {
+                    tracing::warn!("Error while fetching a chunk: {}", e);
+                    return Err(e.into());
+                }
+            };
 
-        if received_bytes + len > slice.len() {
-            return Err(anyhow!("Supplied buffer was too small"));
-        }
+            let len = chunk.len();
+
+            if received_bytes + len > slice.len() {
+                return Err(anyhow!("Supplied buffer was too small"));
+            }
 
-        slice[received_bytes..(received_bytes + len)].copy_from_slice(&chunk);
-        received_bytes += len;
+            slice[received_bytes..(received_bytes + len)].copy_from_slice(&chunk);
+            received_bytes += len;
+        }
     }
 
     Ok(received_bytes)

From 22555cc31a424c9b4c8415961c5155ed2d71a126 Mon Sep 17 00:00:00 2001
From: Andre Guedes <andre.guedes@relational.ai>
Date: Thu, 18 Apr 2024 13:16:44 -0300
Subject: [PATCH 2/2] Adds custom allocator to track memory live_bytes

---
 Cargo.lock          | 196 ++++++++++++++++++++++++++++++++++++++++++--
 Cargo.toml          |  14 +++-
 benches/baseline.rs |  61 ++++++++++++++
 benches/overhead.rs |  61 ++++++++++++++
 src/lib.rs          |  11 +++
 src/metrics.rs      |  93 +++++++++++++++++++++
 6 files changed, 429 insertions(+), 7 deletions(-)
 create mode 100644 benches/baseline.rs
 create mode 100644 benches/overhead.rs
 create mode 100644 src/metrics.rs

diff --git a/Cargo.lock b/Cargo.lock
index c9f8710..9756506 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -41,6 +41,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anes"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b46cbb362ab8752921c97e041f5e366ee6297bd428a31275b9fcf1e380f7299"
+
 [[package]]
 name = "anyhow"
 version = "1.0.75"
@@ -98,6 +104,17 @@ dependencies = [
  "syn 2.0.40",
 ]
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi 0.1.19",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -169,6 +186,12 @@ version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a2bd12c1caf447e69cd4528f47f94d203fd2582878ecb9e9465484c4148a8223"
 
+[[package]]
+name = "cast"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37b2a672a2cb129a2e41c10b1224bb368f9f37a2b16b612598138befd7b37eb5"
+
 [[package]]
 name = "cc"
 version = "1.0.83"
@@ -198,6 +221,54 @@ dependencies = [
  "windows-targets 0.52.0",
 ]
 
+[[package]]
+name = "ciborium"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42e69ffd6f0917f5c029256a24d0161db17cea3997d185db0d35926308770f0e"
+dependencies = [
+ "ciborium-io",
+ "ciborium-ll",
+ "serde",
+]
+
+[[package]]
+name = "ciborium-io"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05afea1e0a06c9be33d539b876f1ce3692f4afea2cb41f740e7743225ed1c757"
+
+[[package]]
+name = "ciborium-ll"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57663b653d948a338bfb3eeba9bb2fd5fcfaecb9e199e87e1eda4d9e8b240fd9"
+dependencies = [
+ "ciborium-io",
+ "half",
+]
+
+[[package]]
+name = "clap"
+version = "3.2.25"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ea181bf566f71cb9a5d17a59e1871af638180a18fb0035c92ae62b705207123"
+dependencies = [
+ "bitflags 1.3.2",
+ "clap_lex",
+ "indexmap 1.9.3",
+ "textwrap",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2850f2f5a82cbf437dd5af4d49848fbdfc27c157c3d010345776f952765261c5"
+dependencies = [
+ "os_str_bytes",
+]
+
 [[package]]
 name = "cmake"
 version = "0.1.50"
@@ -241,6 +312,40 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "criterion"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e7c76e09c1aae2bc52b3d2f29e13c6572553b30c4aa1b8a49fd70de6412654cb"
+dependencies = [
+ "anes",
+ "atty",
+ "cast",
+ "ciborium",
+ "clap",
+ "criterion-plot",
+ "itertools 0.10.5",
+ "lazy_static",
+ "num-traits",
+ "oorandom",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6b50826342786a51a89e2da3a28f1c32b06e387201bc2d19791f622c673706b1"
+dependencies = [
+ "cast",
+ "itertools 0.10.5",
+]
+
 [[package]]
 name = "crossbeam-channel"
 version = "0.5.8"
@@ -283,6 +388,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "crunchy"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a81dae078cea95a014a339291cec439d2f232ebe854a9d672b796c6afafa9b7"
+
 [[package]]
 name = "crypto-common"
 version = "0.1.6"
@@ -540,13 +651,29 @@ dependencies = [
  "futures-sink",
  "futures-util",
  "http",
- "indexmap",
+ "indexmap 2.1.0",
  "slab",
  "tokio",
  "tokio-util",
  "tracing",
 ]
 
+[[package]]
+name = "half"
+version = "2.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6dd08c532ae367adf81c312a4580bc67f1d0fe8bc9c460520283f4c0ff277888"
+dependencies = [
+ "cfg-if",
+ "crunchy",
+]
+
+[[package]]
+name = "hashbrown"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
+
 [[package]]
 name = "hashbrown"
 version = "0.14.3"
@@ -559,6 +686,15 @@ version = "0.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "hermit-abi"
 version = "0.3.3"
@@ -742,6 +878,16 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "indexmap"
+version = "1.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bd070e393353796e801d209ad339e89596eb4c8d430d18ede6a1cced8fafbd99"
+dependencies = [
+ "autocfg",
+ "hashbrown 0.12.3",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.1.0"
@@ -749,7 +895,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d530e1a18b1cb4c484e6e34556a0d948706958449fca0cab753d649f2bce3d1f"
 dependencies = [
  "equivalent",
- "hashbrown",
+ "hashbrown 0.14.3",
 ]
 
 [[package]]
@@ -779,6 +925,15 @@ version = "2.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8f518f335dce6725a761382244631d86cf0ccb2863413590b31338feb467f9c3"
 
+[[package]]
+name = "itertools"
+version = "0.10.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b0fd2260e829bddf4cb6ea802289de2f86d6a7a690192fbe91b3f46e0f2c8473"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools"
 version = "0.12.1"
@@ -980,7 +1135,7 @@ version = "1.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4161fcb6d602d4d2081af7c3a45852d875a03dd337a6bfdd6e06407b61342a43"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.3.3",
  "libc",
 ]
 
@@ -1005,7 +1160,7 @@ dependencies = [
  "futures",
  "humantime",
  "hyper",
- "itertools",
+ "itertools 0.12.1",
  "md-5",
  "parking_lot",
  "percent-encoding",
@@ -1031,6 +1186,7 @@ dependencies = [
  "async-compression",
  "backoff",
  "bytes",
+ "criterion",
  "crossbeam-queue",
  "flate2",
  "futures-util",
@@ -1056,12 +1212,24 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
 
+[[package]]
+name = "oorandom"
+version = "11.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
+
 [[package]]
 name = "openssl-probe"
 version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ff011a302c396a5197692431fc1948019154afc178baf7d8e37367442a4601cf"
 
+[[package]]
+name = "os_str_bytes"
+version = "6.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2355d85b9a3786f481747ced0e0ff2ba35213a1f9bd406ed906554d7af805a1"
+
 [[package]]
 name = "overload"
 version = "0.1.1"
@@ -1633,6 +1801,12 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
 
+[[package]]
+name = "textwrap"
+version = "0.16.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "23d434d3f8967a09480fb04132ebe0a3e088c173e6d0ee7897abbdf4eab0f8b9"
+
 [[package]]
 name = "thiserror"
 version = "1.0.50"
@@ -1655,14 +1829,24 @@ dependencies = [
 
 [[package]]
 name = "thread_local"
-version = "1.1.7"
+version = "1.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3fdd6f064ccff2d6567adcb3873ca630700f00b5ad3f060c25b5dcfd9a4ce152"
+checksum = "8b9ef9bad013ada3808854ceac7b46812a6465ba368859a37e2100283d2d719c"
 dependencies = [
  "cfg-if",
  "once_cell",
 ]
 
+[[package]]
+name = "tinytemplate"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be4d6b5f19ff7664e8c98d03e2139cb510db9b0a60b55f8e8709b689d939b6bc"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "tinyvec"
 version = "1.6.0"
diff --git a/Cargo.toml b/Cargo.toml
index 552a3f2..574b559 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,9 +3,18 @@ name = "object_store_ffi"
 version = "0.6.4"
 edition = "2021"
 
+[[bench]]
+harness = false
+name = "baseline"
+
+[[bench]]
+harness = false
+name = "overhead"
+
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "rlib"]
+bench = false
 
 # https://doc.rust-lang.org/cargo/reference/profiles.html
 [profile.release]
@@ -36,3 +45,6 @@ backoff = "0.4"
 hyper = { version = "0.14", default-features = false }
 flate2 = { version = "1.0.28", features=["zlib-ng"], default-features = false}
 async-compression = { version = "0.4.6", default-features = false, features = ["tokio", "gzip", "zlib", "deflate", "zstd"] }
+
+[dev-dependencies]
+criterion = { version = "0.4", default-features = false, features = ["cargo_bench_support", "html_reports"] }
diff --git a/benches/baseline.rs b/benches/baseline.rs
new file mode 100644
index 0000000..79aec5b
--- /dev/null
+++ b/benches/baseline.rs
@@ -0,0 +1,61 @@
+use std::{time::{Duration, Instant}, sync::atomic::AtomicBool};
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+pub static STOP: AtomicBool = AtomicBool::new(false);
+
+fn criterion_benchmark(c: &mut Criterion) {
+    c.bench_function("system allocation", |b| {
+        // This simply measures the overhead of using the system allocator normally.
+        b.iter(|| Vec::<String>::with_capacity(128));
+    });
+
+    c.bench_function("system allocation multithreaded", |b| {
+        // This simply measures the overhead of using the system allocator normally.
+        b.iter_custom(|iters| {
+            let start = Instant::now();
+            let n = 4;
+            let mut handles = vec![];
+            for _t in 0..n {
+                handles.push(std::thread::spawn(move || {
+                    for _i in 0..(iters / n) {
+                        criterion::black_box(Vec::<String>::with_capacity(128));
+                    }
+                }));
+            }
+
+            for handle in handles {
+                handle.join().unwrap();
+            }
+
+            start.elapsed()
+        });
+    });
+    c.bench_function("system allocation incremental", |b| {
+        // This simply measures the overhead of using the system allocator normally.
+        b.iter_custom(|iters| {
+            let mut data = Vec::with_capacity(100 * 1024 * 1024);
+            let start = Instant::now();
+            for i in 0..iters {
+                if data.len() < 100 * 1024 * 1024 {
+                    data.push(Box::new(i));
+                } else {
+                    data.clear();
+                    data.push(Box::new(i));
+                }
+            }
+            start.elapsed()
+        });
+    });
+}
+
+criterion_group!(
+    name = benches;
+    config = Criterion::default()
+        .significance_level(0.02)
+        .noise_threshold(0.05)
+        .measurement_time(Duration::from_secs(10))
+        .warm_up_time(Duration::from_secs(3));
+    targets = criterion_benchmark
+);
+criterion_main!(benches);
diff --git a/benches/overhead.rs b/benches/overhead.rs
new file mode 100644
index 0000000..871225a
--- /dev/null
+++ b/benches/overhead.rs
@@ -0,0 +1,61 @@
+use std::{sync::atomic::AtomicBool, time::Instant};
+
+use criterion::{criterion_group, criterion_main, Criterion};
+
+pub static STOP: AtomicBool = AtomicBool::new(false);
+
+fn criterion_benchmark(c: &mut Criterion) {
+    c.bench_function("instrumented allocation", |b| {
+        b.iter(|| Vec::<String>::with_capacity(128));
+    });
+
+
+    c.bench_function("instrumented allocation multithreaded", |b| {
+        b.iter_custom(|iters| {
+            let start = Instant::now();
+            let n = 4;
+            let mut handles = vec![];
+            for _t in 0..n {
+                handles.push(std::thread::spawn(move || {
+                    for _i in 0..(iters / n) {
+                        criterion::black_box(Vec::<String>::with_capacity(128));
+                    }
+                }));
+            }
+
+            for handle in handles {
+                handle.join().unwrap();
+            }
+
+            start.elapsed()
+        });
+    });
+
+    c.bench_function("instrumented allocation incremental", |b| {
+        // This simply measures the overhead of using the system allocator normally.
+        b.iter_custom(|iters| {
+            let mut data = Vec::with_capacity(100 * 1024 * 1024);
+            let start = Instant::now();
+            for i in 0..iters {
+                if data.len() < 100 * 1024 * 1024 {
+                    data.push(Box::new(i));
+                } else {
+                    data.clear();
+                    data.push(Box::new(i));
+                }
+            }
+            start.elapsed()
+        });
+    });
+}
+
+criterion_group!(
+    name = benches;
+    config = Criterion::default()
+        .significance_level(0.02)
+        .noise_threshold(0.05)
+        .measurement_time(std::time::Duration::from_secs(10))
+        .warm_up_time(std::time::Duration::from_secs(3));
+    targets = criterion_benchmark
+);
+criterion_main!(benches);
diff --git a/src/lib.rs b/src/lib.rs
index cee30b0..5a831d0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+#[global_allocator]
+static GLOBAL: metrics::InstrumentedAllocator = metrics::InstrumentedAllocator {};
+
 use futures_util::StreamExt;
 use object_store::RetryConfig;
 use once_cell::sync::OnceCell;
@@ -31,6 +34,9 @@ use crud_ops::{handle_get, handle_put, handle_delete, Response};
 mod stream;
 use stream::{handle_get_stream, handle_put_stream, GetStreamResponse, PutStreamResponse};
 
+mod metrics;
+pub use metrics::{InstrumentedAllocator, METRICS};
+
 // Our global variables needed by our library at runtime. Note that we follow Rust's
 // safety rules here by making them immutable with write-exactly-once semantics using
 // either Lazy or OnceCell.
@@ -558,3 +564,8 @@ pub extern "C" fn _trigger_panic() -> CResult {
     });
     CResult::Error
 }
+
+#[no_mangle]
+pub extern "C" fn current_metrics() -> metrics::MetricsSnapshot {
+    metrics::MetricsSnapshot::current()
+}
diff --git a/src/metrics.rs b/src/metrics.rs
new file mode 100644
index 0000000..3357f4b
--- /dev/null
+++ b/src/metrics.rs
@@ -0,0 +1,93 @@
+use std::alloc::{GlobalAlloc, Layout, System};
+use std::sync::atomic::{AtomicI64, Ordering};
+
+#[derive(Debug, Default)]
+#[repr(C)]
+pub struct Metrics {
+    live_bytes: AtomicI64
+}
+
+#[repr(C)]
+pub struct MetricsSnapshot {
+    live_bytes: i64
+}
+
+impl MetricsSnapshot {
+    pub fn current() -> MetricsSnapshot {
+        MetricsSnapshot {
+            live_bytes: METRICS.live_bytes.load(Ordering::Relaxed)
+        }
+    }
+}
+
+impl Metrics {
+    pub const fn new() -> Self {
+        Metrics {
+            live_bytes: AtomicI64::new(0)
+        }
+    }
+}
+
+pub static METRICS: Metrics = Metrics::new();
+
+thread_local! {
+    static LOCAL_METRICS: std::cell::Cell<i64> = const { std::cell::Cell::new(0) };
+}
+
+#[cold]
+fn flush(v: i64) {
+    METRICS.live_bytes.fetch_add(v, Ordering::AcqRel);
+}
+
+pub struct InstrumentedAllocator;
+unsafe impl GlobalAlloc for InstrumentedAllocator {
+    unsafe fn alloc(&self, l: Layout) -> *mut u8 {
+        LOCAL_METRICS.with(|cell| {
+            let live_bytes = cell.get() + (l.size() as i64);
+            if live_bytes  < 100 * 1024 {
+                cell.set(live_bytes);
+            } else {
+                flush(live_bytes);
+                cell.set(0);
+            }
+        });
+        System.alloc(l)
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, l: Layout) {
+        LOCAL_METRICS.with(|cell| {
+            let live_bytes = cell.get() - (l.size() as i64);
+            if live_bytes  > - (100 * 1024) {
+                cell.set(live_bytes);
+            } else {
+                flush(live_bytes);
+                cell.set(0);
+            }
+        });
+        System.dealloc(ptr, l);
+    }
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        LOCAL_METRICS.with(|cell| {
+            let live_bytes = cell.get() + (new_size - layout.size()) as i64;
+            if live_bytes.abs() < 100 * 1024 {
+                cell.set(live_bytes);
+            } else {
+                flush(live_bytes);
+                cell.set(0);
+            }
+        });
+        System.realloc(ptr, layout, new_size)
+    }
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        LOCAL_METRICS.with(|cell| {
+            let live_bytes = cell.get() + (layout.size() as i64);
+            if live_bytes  < 100 * 1024 {
+                cell.set(live_bytes);
+            } else {
+                flush(live_bytes);
+                cell.set(0);
+            }
+        });
+        System.alloc_zeroed(layout)
+    }
+}