Deprecate Stat::cpus field

Summary:
This is a breaking change. New clients will be unable to read old
data.

We are already using Stat::cpus_map which is identical but keyed by
CPU.

Reviewed By: lnyng

Differential Revision: D46946087

fbshipit-source-id: 8eb197e981d1065fa4fd37a7ec634e7ef58b2370

4 files changed, 3 insertions, 26 deletions

diff --git a/below/model/src/system.rs b/below/model/src/system.rs
index 0f300964..438587cd 100644
--- a/below/model/src/system.rs
+++ b/below/model/src/system.rs
@@ -55,7 +55,7 @@ impl SystemModel {
             _ => Default::default(),
         };
 
-        let mut cpus: BTreeMap<u32, SingleCpuModel> = match (
+        let cpus: BTreeMap<u32, SingleCpuModel> = match (
             last.and_then(|(last, _)| last.stat.cpus_map.as_ref()),
             sample.stat.cpus_map.as_ref(),
         ) {
@@ -74,23 +74,6 @@ impl SystemModel {
             _ => Default::default(),
         };
 
-        if cpus.is_empty() {
-            cpus = match (
-                last.and_then(|(last, _)| last.stat.cpus.as_ref()),
-                sample.stat.cpus.as_ref(),
-            ) {
-                (Some(prev), Some(curr)) => std::iter::successors(Some(0), |idx| Some(idx + 1))
-                    .zip(prev.iter().zip(curr.iter()))
-                    .map(|(idx, (prev, curr))| (idx as u32, SingleCpuModel::new(idx, prev, curr)))
-                    .collect(),
-                (_, Some(curr)) => std::iter::successors(Some(0), |idx| Some(idx + 1))
-                    .zip(curr.iter())
-                    .map(|(idx, _curr)| (idx, Default::default()))
-                    .collect(),
-                _ => Default::default(),
-            };
-        }
-
         let mem = Some(MemoryModel::new(&sample.meminfo)).unwrap_or_default();
         let vm = last
             .map(|(last, duration)| VmModel::new(&last.vmstat, &sample.vmstat, duration))
diff --git a/below/procfs/src/lib.rs b/below/procfs/src/lib.rs
index 667d04af..bf43a30a 100644
--- a/below/procfs/src/lib.rs
+++ b/below/procfs/src/lib.rs
@@ -256,7 +256,6 @@ impl ProcReader {
             }
         }
         if !cpus_map.is_empty() {
-            stat.cpus = Some(cpus_map.values().cloned().collect());
             stat.cpus_map = Some(cpus_map);
         }
 
diff --git a/below/procfs/src/test.rs b/below/procfs/src/test.rs
index 3d554cd4..04112ee4 100644
--- a/below/procfs/src/test.rs
+++ b/below/procfs/src/test.rs
@@ -188,11 +188,8 @@ softirq 15518280031 0 3506477306 138437 1090758178 117192437 0 24543 800441241 9
 
     assert_eq!(total_cpu.guest_nice_usec, Some(0));
 
-    let cpu23_from_vec = &stat.cpus.expect("Failed to read cpus")[22];
-    assert_eq!(cpu23_from_vec.user_usec, Some(59379430000));
-
-    let cpu23_from_map = &stat.cpus_map.expect("Failed to read cpus_map")[&23];
-    assert_eq!(cpu23_from_map.user_usec, Some(59379430000));
+    let cpu23 = &stat.cpus_map.expect("Failed to read cpus_map")[&23];
+    assert_eq!(cpu23.user_usec, Some(59379430000));
 
     assert_eq!(stat.total_interrupt_count, Some(29638874355));
     assert_eq!(stat.context_switches, Some(48203489122));
diff --git a/below/procfs/src/types.rs b/below/procfs/src/types.rs
index ae97e267..967769a4 100644
--- a/below/procfs/src/types.rs
+++ b/below/procfs/src/types.rs
@@ -35,8 +35,6 @@ pub struct CpuStat {
 #[derive(Default, Clone, PartialEq, Debug, Serialize, Deserialize)]
 pub struct Stat {
     pub total_cpu: Option<CpuStat>,
-    // TODO: deprecate in favor of cpus_map
-    pub cpus: Option<Vec<CpuStat>>,
     pub cpus_map: Option<BTreeMap<u32, CpuStat>>,
     pub total_interrupt_count: Option<u64>,
     pub context_switches: Option<u64>,