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

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|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*20<br>+1KiB<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>+1KiB<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>
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|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'' 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| 9. ''Canister B'' sends 300-byte response to ''Canister A'' || <code>995'857M</code> || <code>N/A</code><sup>1)</sup> || <code>997'999M</code> || +2*20<br>+300<br><code>≈100M</code><br>(5B limit)
+
|style=text-align:left| 9. ''Canister B'' sends 300-byte response 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)
 
|-
 
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|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 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>
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|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'' 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>
 
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|style=text-align:left| 14. ''Canister A'' sends 500-byte reply to ''User'' || <code>997'953M</code> || +2*20<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>
 
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|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| 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>

Revision as of 11:04, 24 May 2022

This example clarifies the charges in terms of Canister Cycles (i.e. ic0.canister_cycle_balance()) and WASM Instructions (i.e. ic0.performance_counter()).

Setup

  1. There is a User and two Canisters: Canisters A and Canister B
  2. The User sends an 1KiB Ingress Message to Canister A
  3. The Canister A calls Canister B with an 2KiB Update Call
  4. The Canister B replies to Canister A with an 300-byte response
  5. The Canister A replies to User with an 500-byte response

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) -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
-5B/10*4
-2MiB*1K
≈993'897M		 +3*21
+1KiB
≈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 receives a call from Canister A 995'857M N/A1) -590K
≈999'999M		 N/A1)
7. Canister B starts execution 2) 995'857M N/A1) -5B/10*4
≈997'999M		 0
(5B limit)
8. Canister B executes 100M WASM instructions 995'857M N/A1) 997'999M +100M
=100M
(5B limit)
9. Canister B sends 300-byte response to Canister A 995'857M N/A1) 997'999M +2*21
+300
≈100M
(5B limit)
10. Canister B finishes execution 4) 995'857M N/A1) +(5B-100M)*4/10
≈999'959M		 N/A1)
11. Canister A receives a response from Canister B 5) +(2MiB-300)*1K
≈997'953M		 N/A1) 999'959M N/A1)
12. Canister A starts reply callback execution 6) 997'953M 0
(5B limit)		 999'959M N/A1)
13. Canister A executes 100M WASM instructions 997'953M +100M
=100M
(5B limit)		 999'959M N/A1)
14. Canister A sends 500-byte reply to User 997'953M +2*21
+500
≈100M
(5B limit)		 999'959M N/A1)
15. 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:
    260'000
    for the inter-canister call
    2KiB * 1'000
    for byte transmission
    5B/10*4
    for 5B instructions limit to process the response
    2MiB * 1K
    for the maximum response size
  4. The Canister gets a refund for the unused Instructions.
  5. The Canister gets a refund for the unused response 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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