perf: use numbers instead of numeric strings in pprof labels

profiling/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "datadog-php-profiling"
-version = "0.13.0"
+version = "0.14.0"
 edition = "2021"
 license = "Apache-2.0"
 rust-version = "1.60"
@@ -15,7 +15,7 @@ anyhow = { version = "1.0" }
 cfg-if = { version = "1.0" }
 crossbeam-channel = { version = "0.5", default-features = false, features = ["std"] }
 cpu-time = { version = "1.0" }
-datadog-profiling = { git = "https://github.com/DataDog/libdatadog", tag = "v1.0.0" }
+datadog-profiling = { git = "https://github.com/DataDog/libdatadog", tag = "v2.0.0" }
 env_logger = { version = "0.9.3" }
 indexmap = { version = "1.8" }
 lazy_static = { version = "1.4" }

profiling/src/profiling.rs

@@ -13,6 +13,7 @@ use log::{debug, info, trace, warn};
 use std::borrow::{Borrow, Cow};
 use std::collections::HashMap;
 use std::hash::Hash;
+use std::intrinsics::transmute;
 use std::str;
 use std::str::Utf8Error;
 use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
@@ -59,20 +60,18 @@ impl WallTime {
 #[derive(Debug, Clone)]
 pub enum LabelValue {
     Str(Cow<'static, str>),
-
-    #[allow(dead_code)]
-    Num(i64, Cow<'static, str>),
+    Num(i64, Option<&'static str>),
 }
 
 #[derive(Debug, Clone)]
 pub struct Label {
-    pub key: Cow<'static, str>,
+    pub key: &'static str,
     pub value: LabelValue,
 }
 
 impl<'a> From<&'a Label> for profile::api::Label<'a> {
     fn from(label: &'a Label) -> Self {
-        let key = label.key.as_ref();
+        let key = label.key;
         match &label.value {
             LabelValue::Str(str) => Self {
                 key,
@@ -84,7 +83,7 @@ impl<'a> From<&'a Label> for profile::api::Label<'a> {
                 key,
                 str: None,
                 num: *num,
-                num_unit: Some(num_unit),
+                num_unit: num_unit.as_deref(),
             },
         }
     }
@@ -388,9 +387,9 @@ impl TimeCollector {
             "Received Endpoint Profiling message for span id {}.",
             message.local_root_span_id
         );
-        let local_root_span_id = message.local_root_span_id.to_string();
+
+        let local_root_span_id = message.local_root_span_id;
         for (_, profile) in profiles.iter_mut() {
-            let local_root_span_id = Cow::Borrowed(local_root_span_id.as_ref());
             let endpoint = Cow::Borrowed(message.resource.as_str());
             profile.add_endpoint(local_root_span_id, endpoint)
         }
@@ -832,13 +831,20 @@ impl Profiler {
         if let Some(get_profiling_context) = gpc {
             let context = unsafe { get_profiling_context() };
             if context.local_root_span_id != 0 {
+                /* Safety: PProf only has signed integers for label.num.
+                 * We bit-cast u64 to i64, and the backend does the
+                 * reverse so the conversion is lossless.
+                 */
+                let local_root_span_id: i64 = unsafe { transmute(context.local_root_span_id) };
+                let span_id: i64 = unsafe { transmute(context.span_id) };
+
                 labels.push(Label {
-                    key: "local root span id".into(),
-                    value: LabelValue::Str(format!("{}", context.local_root_span_id).into()),
+                    key: "local root span id",
+                    value: LabelValue::Num(local_root_span_id, None),
                 });
                 labels.push(Label {
-                    key: "span id".into(),
-                    value: LabelValue::Str(format!("{}", context.span_id).into()),
+                    key: "span id",
+                    value: LabelValue::Num(span_id, None),
                 });
             }
         }