microsoft / microsoft/ntttcp-for-linux

Avoid using atomic primitives in the hot path

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Dominant language
C
Stars
426
Forks
108
PR merge metrics
No merged PRs in 30d

Description

For instance, in tcpstream.c and udpstream.c, __sync_fetch_and_add() is used to update the number of bytes transferred. This can cause contention between cores if they share cache lines (i.e. false sharing). Ideally, each thread would update their own counter without any kind of locking, and these numbers would be tallied up after joining the worker threads.

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Research direction

Start by reading the counter updates in tcpstream.c and udpstream.c, then trace how worker threads are created and joined. Determine how each thread's byte count can be retained and aggregated after joining without atomic updates. Done means the hot-path counters no longer use __sync_fetch_and_add() and the benchmark still builds and reports the totals correctly.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
networking, performance
Issue type
Refactor
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
42/100

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