Removing dependency to num_cpus (as the info is available in the std (#…

…4947)

* Removing dependency to num_cpus (as the info is available in the std
nowadays).

* Added error behavior following CR

quickwit/Cargo.toml

@@ -155,7 +155,6 @@ mockall = "0.11"
 mrecordlog = { git = "https://github.com/quickwit-oss/mrecordlog", rev = "306c0a7" }
 new_string_template = "1.5.1"
 nom = "7.1.3"
-num_cpus = "1"
 numfmt = "1.1.1"
 once_cell = "1"
 oneshot = "0.1.5"

quickwit/quickwit-common/Cargo.toml

@@ -25,7 +25,6 @@ hostname = { workspace = true }
 http = { workspace = true }
 hyper = { workspace = true }
 itertools = { workspace = true }
-num_cpus = { workspace = true }
 once_cell = { workspace = true }
 pin-project = { workspace = true }
 pnet = { workspace = true }

quickwit/quickwit-common/src/lib.rs

@@ -173,6 +173,18 @@ pub const fn div_ceil(lhs: i64, rhs: i64) -> i64 {
     }
 }
 
+/// Return the number of vCPU/hyperthreads available.
+/// This number is usually not equal to the number of cpu cores
+pub fn num_cpus() -> usize {
+    match std::thread::available_parallelism() {
+        Ok(num_cpus) => num_cpus.get(),
+        Err(io_err) => {
+            error!(err=?io_err, "fail to detect the amount of threads available. arbitrarily returning 2");
+            2
+        }
+    }
+}
+
 // The following are helpers to build named tasks.
 //
 // Named tasks require the tokio feature `tracing` to be enabled.

quickwit/quickwit-common/src/runtimes.rs

@@ -77,7 +77,7 @@ impl RuntimesConfig {
 
 impl Default for RuntimesConfig {
     fn default() -> Self {
-        let num_cpus = num_cpus::get();
+        let num_cpus = crate::num_cpus();
         Self::with_num_cpus(num_cpus)
     }
 }

quickwit/quickwit-config/Cargo.toml

@@ -23,7 +23,6 @@ humantime = { workspace = true }
 itertools = { workspace = true }
 json_comments = { workspace = true }
 new_string_template = { workspace = true }
-num_cpus = { workspace = true }
 once_cell = { workspace = true }
 regex = { workspace = true }
 serde = { workspace = true }

quickwit/quickwit-config/src/node_config/mod.rs

@@ -138,11 +138,12 @@ impl IndexerConfig {
     }
 
     pub fn default_merge_concurrency() -> NonZeroUsize {
-        NonZeroUsize::new(num_cpus::get() * 2 / 3).unwrap_or(NonZeroUsize::new(1).unwrap())
+        NonZeroUsize::new(quickwit_common::num_cpus() * 2 / 3)
+            .unwrap_or(NonZeroUsize::new(1).unwrap())
     }
 
     fn default_cpu_capacity() -> CpuCapacity {
-        CpuCapacity::one_cpu_thread() * (num_cpus::get() as u32)
+        CpuCapacity::one_cpu_thread() * (quickwit_common::num_cpus() as u32)
     }
 
     #[cfg(any(test, feature = "testsuite"))]

quickwit/quickwit-serve/Cargo.toml

@@ -27,7 +27,6 @@ humantime = { workspace = true }
 hyper = { workspace = true }
 itertools = { workspace = true }
 mime_guess = { workspace = true }
-num_cpus = { workspace = true }
 once_cell = { workspace = true }
 opentelemetry = { workspace = true }
 percent-encoding = { workspace = true }

quickwit/quickwit-serve/src/build_info.rs

@@ -96,8 +96,9 @@ impl BuildInfo {
 
 #[derive(Debug, Eq, PartialEq, Serialize, utoipa::ToSchema)]
 pub struct RuntimeInfo {
-    pub num_cpus_logical: usize,
-    pub num_cpus_physical: usize,
+    // This is a number of logical cpus: vCPU or hyperthread depending on where you are running.
+    // This is usually NOT necessarily the number of cores.
+    pub num_cpus: usize,
     pub num_threads_blocking: usize,
     pub num_threads_non_blocking: usize,
 }
@@ -108,12 +109,10 @@ impl RuntimeInfo {
         static INSTANCE: OnceCell<RuntimeInfo> = OnceCell::new();
 
         INSTANCE.get_or_init(|| {
-            let num_cpus_logical = num_cpus::get();
-            let runtimes_config = RuntimesConfig::with_num_cpus(num_cpus_logical);
-
+            let num_cpus = quickwit_common::num_cpus();
+            let runtimes_config = RuntimesConfig::with_num_cpus(num_cpus);
             Self {
-                num_cpus_logical,
-                num_cpus_physical: num_cpus::get_physical(),
+                num_cpus,
                 num_threads_blocking: runtimes_config.num_threads_blocking,
                 num_threads_non_blocking: runtimes_config.num_threads_non_blocking,
             }

quickwit/quickwit-serve/src/node_info_handler.rs

@@ -105,7 +105,7 @@ mod tests {
 
         let runtime_info_json = info_json.get("runtime").unwrap();
         let expected_runtime_info_json = serde_json::json!({
-            "num_cpus_physical": runtime_info.num_cpus_physical,
+            "num_cpus": runtime_info.num_cpus,
         });
         assert_json_include!(
             actual: runtime_info_json,