Difference between revisions of "Comparing Canister Cycles vs Performance Counter"

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|style=text-align:left| 2. ''Canister A'' receives 1KiB ''Ingress Message'' || -1,2M<br>-1KiB*2K<br><code>≈999'996M</code> || <code>N/A</code><sup>1)</sup> || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|style=text-align:left| 2. ''Canister A'' receives 1KiB ''Ingress Message'' || -1,2M<br>-1KiB*2K<br><code>≈999'996M</code> || <code>N/A</code><sup>1)</sup> || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 3. ''Canister A'' starts execution <sup>2)</sup> || -5B/10*4<br><code>≈997'996M</code> || <code>0</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 3. ''Canister A'' starts execution <sup>2)</sup> || -590K<br>-5B/10*4<br><code>≈997'996M</code> || <code>0</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
 
|style=text-align:left| 4. ''Canister A'' executes 100M WASM instructions || <code>997'996M</code> || +100M<br><code>=100M</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|style=text-align:left| 4. ''Canister A'' executes 100M WASM instructions || <code>997'996M</code> || +100M<br><code>=100M</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 5. ''Canister A'' sends 2KiB call to ''Canister B'' <sup>3)</sup> || -260K<br>-2KiB*1K<br>-5B/10*4<br>-2MiB*1K<br><code>≈993'897M</code> || +3*21<br>+2KiB<br><code>≈100M</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 5. ''Canister A'' sends 2KiB call to ''Canister B'' <sup>3)</sup> || -260K<br>-2KiB*1K<br>-2MiB*1K<br>-590K<br>-5B/10*4<br><code>≈993'897M</code> || +3*21<br>+2KiB<br><code>≈100M</code><br>(5B limit) || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
 
|style=text-align:left| 5. ''Canister A'' finishes execution <sup>4)</sup> || +(5B-100M)*4/10<br><code>≈995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|style=text-align:left| 5. ''Canister A'' finishes execution <sup>4)</sup> || +(5B-100M)*4/10<br><code>≈995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>1T</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 6. ''Canister B'' receives a call from ''Canister A'' || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || -590K<br><code>≈999'999M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 6. ''Canister B'' starts execution <sup>2)</sup>|| <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || -590K<br>-5B/10*4<br><code>≈997'999M</code> || <code>0</code><br>(5B limit)
 
|-
 
|-
−
|style=text-align:left| 7. ''Canister B'' starts execution <sup>2)</sup>|| <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || -5B/10*4<br><code>≈997'999M</code> || <code>0</code><br>(5B limit)
+
|style=text-align:left| 7. ''Canister B'' executes 100M WASM instructions || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>997'999M</code> || +100M<br><code>=100M</code><br>(5B limit)
 
|-
 
|-
−
|style=text-align:left| 8. ''Canister B'' executes 100M WASM instructions || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>997'999M</code> || +100M<br><code>=100M</code><br>(5B limit)
+
|style=text-align:left| 8. ''Canister B'' sends 300-byte reply to ''Canister A'' || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>997'999M</code> || +2*21<br>+300<br><code>≈100M</code><br>(5B limit)
 
|-
 
|-
−
|style=text-align:left| 9. ''Canister B'' sends 300-byte reply to ''Canister A'' || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>997'999M</code> || +2*21<br>+300<br><code>≈100M</code><br>(5B limit)
+
|style=text-align:left| 9. ''Canister B'' finishes execution <sup>4)</sup> || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || +(5B-100M)*4/10<br><code>≈999'959M</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 10. ''Canister B'' finishes execution <sup>4)</sup> || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || +(5B-100M)*4/10<br><code>≈999'959M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 10. ''Canister A'' receives a reply from ''Canister B'' <sup>5)</sup> || +(2MiB-300)*1K<br><code>≈997'953M</code> || <code>N/A</code><sup>1)</sup> || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 11. ''Canister A'' receives a reply from ''Canister B'' <sup>5)</sup> || +(2MiB-300)*1K<br><code>≈997'953M</code> || <code>N/A</code><sup>1)</sup> || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 11. ''Canister A'' starts reply callback execution <sup>6)</sup> || <code>997'953M</code> || <code>0</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 12. ''Canister A'' starts reply callback execution <sup>6)</sup> || <code>997'953M</code> || <code>0</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 12. ''Canister A'' executes 100M WASM instructions || <code>997'953M</code> || +100M<br><code>=100M</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 13. ''Canister A'' executes 100M WASM instructions || <code>997'953M</code> || +100M<br><code>=100M</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 13. ''Canister A'' sends 500-byte reply to ''User'' || <code>997'953M</code> || +2*21<br>+500<br><code>≈100M</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
 
|-
 
|-
−
|style=text-align:left| 14. ''Canister A'' sends 500-byte reply to ''User'' || <code>997'953M</code> || +2*21<br>+500<br><code>≈100M</code><br>(5B limit) || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
+
|style=text-align:left| 14. ''Canister A'' finishes execution <sup>4)</sup> || +(5B-100M)*4/10<br><code>≈999'913M</code> || <code>N/A</code><sup>1)</sup> || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
−
|-
 
−
|style=text-align:left| 15. ''Canister A'' finishes execution <sup>4)</sup> || +(5B-100M)*4/10<br><code>≈999'913M</code> || <code>N/A</code><sup>1)</sup> || <code>999'959M</code> || <code>N/A</code><sup>1)</sup>
 
 
|-
 
|-
 
!style=text-align:left| Total: !! <code>~87M Cycles</code><br>for ~200M WASM Instructions Executed<br>+ messaging !!  !! <code>~41M Cycles</code><br>for ~100M WASM Instructions Executed<br>+ messaging !!
 
!style=text-align:left| Total: !! <code>~87M Cycles</code><br>for ~200M WASM Instructions Executed<br>+ messaging !!  !! <code>~41M Cycles</code><br>for ~100M WASM Instructions Executed<br>+ messaging !!
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# At the moment, there is a 5B instructions limit per normal message execution, so the Canister get charged for the maximum amount of Instructions it can potentially execute.
 
# At the moment, there is a 5B instructions limit per normal message execution, so the Canister get charged for the maximum amount of Instructions it can potentially execute.
 
# The Canister get charged:
 
# The Canister get charged:
−
#; 260'000 : for the inter-canister call
+
#; 260K : for the inter-canister call
 
#; 2KiB * 1'000 : for byte transmission
 
#; 2KiB * 1'000 : for byte transmission
 +
#; 2MiB * 1K : for the maximum reply size
 +
#; 590K : for the reply message execution
 
#; 5B/10*4 : for 5B instructions limit to process the reply
 
#; 5B/10*4 : for 5B instructions limit to process the reply
−
#; 2MiB * 1K : for the maximum reply size
 
 
# The Canister gets a refund for the unused Instructions.
 
# The Canister gets a refund for the unused Instructions.
 
# The Canister gets a refund for the unused reply bytes.
 
# The Canister gets a refund for the unused reply bytes.

Revision as of 15:40, 24 May 2022

The example walks through a scenario of charging cycles that includes inter-canister calls and how the performance counter relates to the work done by canisters.

Setup

  1. The User sends an 1KiB Ingress Message to Canister A
  2. The Canister A calls Canister B with an 2KiB Update Call
  3. The Canister B responds to Canister A with an 300-byte reply
  4. The Canister A responds to User with an 500-byte reply

Example Cycles Flow

Naming conventions:

  • 1K == 1'000
  • 1KiB == 1'024 bytes
  • 1M == 1'000'000
  • 1MiB == 1'048'576 bytes
  • 1B == 1'000'000'000
  • 1T == 1'000'000'000'000
What is Happening Canister A
Cycles Balance		 Canister A
Perf Counter		 Canister B
Cycles Balance		 Canister B
Perf Counter
1. Initial state 1T N/A1) 1T N/A1)
2. Canister A receives 1KiB Ingress Message -1,2M
-1KiB*2K
≈999'996M		 N/A1) 1T N/A1)
3. Canister A starts execution 2) -590K
-5B/10*4
≈997'996M		 0
(5B limit)		 1T N/A1)
4. Canister A executes 100M WASM instructions 997'996M +100M
=100M
(5B limit)		 1T N/A1)
5. Canister A sends 2KiB call to Canister B 3) -260K
-2KiB*1K
-2MiB*1K
-590K
-5B/10*4
≈993'897M		 +3*21
+2KiB
≈100M
(5B limit)		 1T N/A1)
5. Canister A finishes execution 4) +(5B-100M)*4/10
≈995'857M		 N/A1) 1T N/A1)
6. Canister B starts execution 2) 995'857M N/A1) -590K
-5B/10*4
≈997'999M		 0
(5B limit)
7. Canister B executes 100M WASM instructions 995'857M N/A1) 997'999M +100M
=100M
(5B limit)
8. Canister B sends 300-byte reply to Canister A 995'857M N/A1) 997'999M +2*21
+300
≈100M
(5B limit)
9. Canister B finishes execution 4) 995'857M N/A1) +(5B-100M)*4/10
≈999'959M		 N/A1)
10. Canister A receives a reply from Canister B 5) +(2MiB-300)*1K
≈997'953M		 N/A1) 999'959M N/A1)
11. Canister A starts reply callback execution 6) 997'953M 0
(5B limit)		 999'959M N/A1)
12. Canister A executes 100M WASM instructions 997'953M +100M
=100M
(5B limit)		 999'959M N/A1)
13. Canister A sends 500-byte reply to User 997'953M +2*21
+500
≈100M
(5B limit)		 999'959M N/A1)
14. Canister A finishes execution 4) +(5B-100M)*4/10
≈999'913M		 N/A1) 999'959M N/A1)
Total: ~87M Cycles
for ~200M WASM Instructions Executed
+ messaging		 ~41M Cycles
for ~100M WASM Instructions Executed
+ messaging


Notes:

  1. The Performance Counter is available only during execution, so it's marked as N/A when the execution has not started yet.
  2. At the moment, there is a 5B instructions limit per normal message execution, so the Canister get charged for the maximum amount of Instructions it can potentially execute.
  3. The Canister get charged:
    260K
    for the inter-canister call
    2KiB * 1'000
    for byte transmission
    2MiB * 1K
    for the maximum reply size
    590K
    for the reply message execution
    5B/10*4
    for 5B instructions limit to process the reply
  4. The Canister gets a refund for the unused Instructions.
  5. The Canister gets a refund for the unused reply bytes.
  6. The Canister has already been charged for the reply callback.

References

  1. The Internet Computer Interface Specification
  2. The Internet Computer Computation and Storage Costs
  3. Community Conversations | Charging Canister Cycles
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