Use the default pipe options for backpressure

[davidfowl]

• This controls memory so clients aren't easily overwhelmed. With the changes made to Pipe to no longer throw if the pause threshold is exceeded makes this work well.

Contributes to #17797

Here's the sample from #20654

Before:

After:

[davidfowl]

/azp run aspnetcore-ci (Build Tests: Helix x64)

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[davidfowl]

/azp run aspnetcore-ci Helix x64)

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No pipelines are associated with this pull request.

[davidfowl]

/azp run aspnetcore-ci Helix x64

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No pipelines are associated with this pull request.

[davidfowl]

/azp run aspnetcore-ci (Build Tests: Helix x64)

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No pipelines are associated with this pull request.

[davidfowl]

/azp run

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Azure Pipelines successfully started running 2 pipeline(s).

[BrennanConroy]

Are we not going to add the option in this PR?

[davidfowl]

Are we not going to add the option in this PR?

I chose not to but I can. That's why I wrote contributes to vs fixes. The option isn't as important anymore because it's no longer a hard limit in pipes.

[BrennanConroy]

Does this affect throughput significantly?

[davidfowl]

Does this affect throughput significantly?

In this test it improves throughput since the GC is basically bringing the application to its knees. I haven't run any benchmarks though.

[davidfowl]

Before

Counters:

CPU Usage (%):                 58
Working Set (MB):              75
GC Heap Size (MB):             13
Gen 0 GC (#/s):                36
Gen 1 GC (#/s):                4
Gen 2 GC (#/s):                0
Time in GC (%):                12
Gen 0 Size (B):                180,784
Gen 1 Size (B):                1,154,376
Gen 2 Size (B):                13,742,736
LOH Size (B):                  48,416
Allocation Rate (B/sec):       272,120,129
# of Assemblies Loaded:        66
Exceptions (#/s):              0
ThreadPool Threads Count:      43
Lock Contention (#/s):         959
ThreadPool Queue Length:       65
ThreadPool Items (#/s):        244,659

Benchmark:

Max RPS:                       593,436
Requests:                      8,918,162
Mean latency (ms):             9

After

Counters:

CPU Usage (%):                 63
Working Set (MB):              68
GC Heap Size (MB):             13
Gen 0 GC (#/s):                32
Gen 1 GC (#/s):                3
Gen 2 GC (#/s):                0
Time in GC (%):                10
Gen 0 Size (B):                274,304
Gen 1 Size (B):                1,048,648
Gen 2 Size (B):                12,286,616
LOH Size (B):                  48,416
Allocation Rate (B/sec):       239,139,013
# of Assemblies Loaded:        65
Exceptions (#/s):              0
ThreadPool Threads Count:      56
Lock Contention (#/s):         926
ThreadPool Queue Length:       79
ThreadPool Items (#/s):        290,194

Benchmark:

Max RPS:                       561,548
Requests:                      8,444,560
Mean latency (ms):             5

Slightly slower on our broadcast benchmark same on echo.

[davidfowl]

/azp run

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Azure Pipelines successfully started running 2 pipeline(s).