First implementation of cache memory data collection, mostly copied from RAM and swap implementations

src/app/data_farmer.rs

@@ -37,6 +37,7 @@ pub struct TimedData {
     pub cpu_data: Vec<Value>,
     pub load_avg_data: [f32; 3],
     pub mem_data: Option<Value>,
+    pub cache_data: Option<Value>,
     pub swap_data: Option<Value>,
     #[cfg(feature = "zfs")]
     pub arc_data: Option<Value>,
@@ -110,6 +111,7 @@ pub struct DataCollection {
     pub timed_data_vec: Vec<(Instant, TimedData)>,
     pub network_harvest: network::NetworkHarvest,
     pub memory_harvest: memory::MemHarvest,
+    pub cache_harvest: memory::MemHarvest,
     pub swap_harvest: memory::MemHarvest,
     pub cpu_harvest: cpu::CpuHarvest,
     pub load_avg_harvest: cpu::LoadAvgHarvest,
@@ -134,6 +136,7 @@ impl Default for DataCollection {
             timed_data_vec: Vec::default(),
             network_harvest: network::NetworkHarvest::default(),
             memory_harvest: memory::MemHarvest::default(),
+            cache_harvest: memory::MemHarvest::default(),
             swap_harvest: memory::MemHarvest::default(),
             cpu_harvest: cpu::CpuHarvest::default(),
             load_avg_harvest: cpu::LoadAvgHarvest::default(),
@@ -209,8 +212,8 @@ impl DataCollection {
         }
 
         // Memory and Swap
-        if let (Some(memory), Some(swap)) = (harvested_data.memory, harvested_data.swap) {
-            self.eat_memory_and_swap(memory, swap, &mut new_entry);
+        if let (Some(memory), Some(cache), Some(swap)) = (harvested_data.memory, harvested_data.cache, harvested_data.swap) {
+            self.eat_memory_and_swap(memory, cache, swap, &mut new_entry);
         }
 
         #[cfg(feature = "zfs")]
@@ -264,16 +267,20 @@ impl DataCollection {
     }
 
     fn eat_memory_and_swap(
-        &mut self, memory: memory::MemHarvest, swap: memory::MemHarvest, new_entry: &mut TimedData,
+        &mut self, memory: memory::MemHarvest, cache: memory::MemHarvest, swap: memory::MemHarvest, new_entry: &mut TimedData,
     ) {
         // Memory
         new_entry.mem_data = memory.use_percent;
 
+        // Cache
+        new_entry.cache_data = cache.use_percent;
+
         // Swap
         new_entry.swap_data = swap.use_percent;
 
         // In addition copy over latest data for easy reference
         self.memory_harvest = memory;
+        self.cache_harvest = cache;
         self.swap_harvest = swap;
     }
 

src/app/data_harvester.rs

@@ -34,6 +34,7 @@ pub struct Data {
     pub cpu: Option<cpu::CpuHarvest>,
     pub load_avg: Option<cpu::LoadAvgHarvest>,
     pub memory: Option<memory::MemHarvest>,
+    pub cache: Option<memory::MemHarvest>,
     pub swap: Option<memory::MemHarvest>,
     pub temperature_sensors: Option<Vec<temperature::TempHarvest>>,
     pub network: Option<network::NetworkHarvest>,
@@ -55,6 +56,7 @@ impl Default for Data {
             cpu: None,
             load_avg: None,
             memory: None,
+            cache: None,
             swap: None,
             temperature_sensors: None,
             list_of_processes: None,
@@ -397,6 +399,7 @@ impl DataCollector {
     fn update_memory_usage(&mut self) {
         if self.widgets_to_harvest.use_mem {
             self.data.memory = memory::get_ram_usage(&self.sys);
+            self.data.cache = memory::get_cache_usage(&self.sys);
             self.data.swap = memory::get_swap_usage(
                 #[cfg(not(target_os = "windows"))]
                 &self.sys,

src/app/data_harvester/memory.rs

@@ -2,6 +2,7 @@
 
 pub mod sysinfo;
 pub(crate) use self::sysinfo::get_ram_usage;
+pub(crate) use self::sysinfo::get_cache_usage;
 
 cfg_if::cfg_if! {
     if #[cfg(target_os = "windows")] {

src/app/data_harvester/memory/sysinfo.rs

@@ -36,3 +36,19 @@ pub(crate) fn get_swap_usage(sys: &System) -> Option<MemHarvest> {
         },
     })
 }
+
+/// Returns cache usage.
+pub(crate) fn get_cache_usage(sys: &System) -> Option<MemHarvest> {
+    let mem_used_in_kib = (sys.available_memory() - sys.free_memory()) / 1024;
+    let mem_total_in_kib = sys.total_memory() / 1024;
+
+    Some(MemHarvest {
+        total_kib: mem_total_in_kib,
+        used_kib: mem_used_in_kib,
+        use_percent: if mem_total_in_kib == 0 {
+            None
+        } else {
+            Some(mem_used_in_kib as f64 / mem_total_in_kib as f64 * 100.0)
+        },
+    })
+}

src/data_conversion.rs

@@ -68,9 +68,11 @@ pub struct ConvertedData {
     pub network_data_tx: Vec<Point>,
 
     pub mem_labels: Option<(String, String)>,
+    pub cache_labels: Option<(String, String)>,
     pub swap_labels: Option<(String, String)>,
 
     pub mem_data: Vec<Point>, /* TODO: Switch this and all data points over to a better data structure... */
+    pub cache_data: Vec<Point>,
     pub swap_data: Vec<Point>,
 
     #[cfg(feature = "zfs")]
@@ -218,6 +220,24 @@ pub fn convert_mem_data_points(current_data: &DataCollection) -> Vec<Point> {
     result
 }
 
+pub fn convert_cache_data_points(current_data: &DataCollection) -> Vec<Point> {
+    let mut result: Vec<Point> = Vec::new();
+    let current_time = current_data.current_instant;
+
+    for (time, data) in &current_data.timed_data_vec {
+        if let Some(cache_data) = data.cache_data {
+            let time_from_start: f64 =
+                (current_time.duration_since(*time).as_millis() as f64).floor();
+            result.push((-time_from_start, cache_data));
+            if *time == current_time {
+                break;
+            }
+        }
+    }
+
+    result
+}
+
 pub fn convert_swap_data_points(current_data: &DataCollection) -> Vec<Point> {
     let mut result: Vec<Point> = Vec::new();
     let current_time = current_data.current_instant;
@@ -238,7 +258,7 @@ pub fn convert_swap_data_points(current_data: &DataCollection) -> Vec<Point> {
 
 pub fn convert_mem_labels(
     current_data: &DataCollection,
-) -> (Option<(String, String)>, Option<(String, String)>) {
+) -> (Option<(String, String)>, Option<(String, String)>, Option<(String, String)>) {
     /// Returns the unit type and denominator for given total amount of memory in kibibytes.
     fn return_unit_and_denominator_for_mem_kib(mem_total_kib: u64) -> (&'static str, f64) {
         if mem_total_kib < 1024 {
@@ -280,6 +300,29 @@ pub fn convert_mem_labels(
         } else {
             None
         },
+        if current_data.cache_harvest.total_kib > 0 {
+            Some((
+                format!(
+                    "{:3.0}%",
+                    current_data.cache_harvest.use_percent.unwrap_or(0.0)
+                ),
+                {
+                    let (unit, denominator) = return_unit_and_denominator_for_mem_kib(
+                        current_data.cache_harvest.total_kib,
+                    );
+
+                    format!(
+                        "   {:.1}{}/{:.1}{}",
+                        current_data.cache_harvest.used_kib as f64 / denominator,
+                        unit,
+                        (current_data.cache_harvest.total_kib as f64 / denominator),
+                        unit
+                    )
+                },
+            ))
+        } else {
+            None
+        },
         if current_data.swap_harvest.total_kib > 0 {
             Some((
                 format!(

src/lib.rs

@@ -386,6 +386,7 @@ pub fn update_data(app: &mut App) {
     // TODO: [OPT] Prefer reassignment over new vectors?
     if app.mem_state.force_update.is_some() {
         app.converted_data.mem_data = convert_mem_data_points(data_source);
+        app.converted_data.cache_data = convert_cache_data_points(data_source);
         app.converted_data.swap_data = convert_swap_data_points(data_source);
         #[cfg(feature = "zfs")]
         {