vault backup: 2023-10-04 12:43:31

4a1s/CP/PL - Aula 4.md

@@ -51,7 +51,7 @@ Ganhos de 4 vezes mais.
 
 
 
-
+----
 ## Ex. 3
 #### a) Peak Performance
 2 operações em FP
@@ -60,6 +60,15 @@ Ganhos de 4 vezes mais.
 
 conclusion: 20 GFlop/s
 
+>[!note]- Redoing the math
+>AVX -> 256b -> 4 doubles
+>machine is superscalar with 2 FOP units
+>4x2= 8 double-perations 
+>
+>freq = 2.5 GHz
+>8x2.5= 20 GFlop/s
+>            ^ cpu limitiation
+
 #### b)
 peak with vectorization: continuous 20 GFlop/s
 peak without vectorization: continuous 5 GFlop/s
@@ -67,8 +76,8 @@ memory bandwith limitation: ***see alinea d)***
 real achievable performance:***see alinea c)***
 measured performance:
 
-#### d)
-memory bandwith limitation
+#### d) Memory bandwidth limitation
+1 FOP -> 2B
 
 | GFlop/s | Flop/Byte |
 | ------- | --------- |
@@ -88,6 +97,4 @@ memory bandwith limitation
 | ------- | --------- |
 | 0.125   | 2.5       |
 
-
-#### d)
-AVX -> 256b -> 4 doubles
+#### e)