Re: [pbs-devel] [PATCH proxmox-backup 14/15] proxmox-rrd: rename last_counter to last_value

[Dietmar Maurer <dietmar@proxmox.com>]

This introduces a bug: here is the fix

diff --git a/proxmox-rrd/src/rrd.rs b/proxmox-rrd/src/rrd.rs
index c6996e42..eb6154e7 100644
--- a/proxmox-rrd/src/rrd.rs
+++ b/proxmox-rrd/src/rrd.rs
@@ -107,11 +107,12 @@ impl DataSource {
             } else {
                 value - self.last_value
             };
+            self.last_value = value;
             value = diff/time_diff;
+        } else {
+            self.last_value = value;
         }
 
-        self.last_value = value;
-
         Ok(value)
     }
 



> On 10/13/2021 10:24 AM Dietmar Maurer <dietmar@proxmox.com> wrote:
> 
>  
> ---
>  proxmox-rrd/src/rrd.rs    | 25 +++++++++++++++----------
>  proxmox-rrd/src/rrd_v1.rs |  2 +-
>  2 files changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/proxmox-rrd/src/rrd.rs b/proxmox-rrd/src/rrd.rs
> index 7901fe39..72769bfd 100644
> --- a/proxmox-rrd/src/rrd.rs
> +++ b/proxmox-rrd/src/rrd.rs
> @@ -63,7 +63,7 @@ pub struct DataSource {
>      pub last_update: f64,
>      /// Stores the last value, used to compute differential value for
>      /// derive/counters
> -    pub counter_value: f64,
> +    pub last_value: f64,
>  }
>  
>  impl DataSource {
> @@ -72,7 +72,7 @@ impl DataSource {
>          Self {
>              dst,
>              last_update: 0.0,
> -            counter_value: f64::NAN,
> +            last_value: f64::NAN,
>          }
>      }
>  
> @@ -94,23 +94,24 @@ impl DataSource {
>          if is_counter || self.dst == DST::Derive {
>              let time_diff = time - self.last_update;
>  
> -            let diff = if self.counter_value.is_nan() {
> +            let diff = if self.last_value.is_nan() {
>                  0.0
>              } else if is_counter && value < 0.0 {
>                  bail!("got negative value for counter");
> -            } else if is_counter && value < self.counter_value {
> +            } else if is_counter && value < self.last_value {
>                  // Note: We do not try automatic overflow corrections, but
> -                // we update counter_value anyways, so that we can compute the diff
> +                // we update last_value anyways, so that we can compute the diff
>                  // next time.
> -                self.counter_value = value;
> +                self.last_value = value;
>                  bail!("conter overflow/reset detected");
>              } else {
> -                value - self.counter_value
> +                value - self.last_value
>              };
> -            self.counter_value = value;
>              value = diff/time_diff;
>          }
>  
> +        self.last_value = value;
> +
>          Ok(value)
>      }
>  
> @@ -138,11 +139,15 @@ impl RRA {
>          }
>      }
>  
> -    fn slot_end_time(&self, time: u64) -> u64 {
> +    pub fn slot_end_time(&self, time: u64) -> u64 {
>          self.resolution*(time/self.resolution + 1)
>      }
>  
> -    fn slot(&self, time: u64) -> usize {
> +    pub fn slot_start_time(&self, time: u64) -> u64 {
> +        self.resolution*(time/self.resolution)
> +    }
> +
> +    pub fn slot(&self, time: u64) -> usize {
>          ((time/self.resolution) as usize) % self.data.len()
>      }
>  
> diff --git a/proxmox-rrd/src/rrd_v1.rs b/proxmox-rrd/src/rrd_v1.rs
> index 511b510b..7e4b97c2 100644
> --- a/proxmox-rrd/src/rrd_v1.rs
> +++ b/proxmox-rrd/src/rrd_v1.rs
> @@ -285,7 +285,7 @@ impl RRDv1 {
>  
>          let source = DataSource {
>              dst,
> -            counter_value: f64::NAN,
> +            last_value: f64::NAN,
>              last_update:  self.hour_avg.last_update, // IMPORTANT!
>          };
>          Ok(RRD {
> -- 
> 2.30.2