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- There are multiple inconsistency and incorrect way in which rw-lock stats are calculated. - shared rw-lock stats: "rounds" counter is incremented only once for N rounds done in spin-cycle. - all rw-lock stats: If the spin-cycle is short-circuited then attempts are re-counted. [If spin-cycle is interrupted, before it completes srv_n_spin_wait_rounds (default 30) rounds, spin_count is incremented to consider this. If thread resumes spin-cycle (due to unavailability of the locks) and is again interrupted or completed, spin_count is again incremented with the total count, failing to adjust the previous attempt increment]. - s/x rw-lock stats: spin_loop counter is not incremented at-all instead it is projected as 0 (in show engine output) and division to calculate spin-round per spin-loop is adjusted. As per the original semantics spin_loop counter should be incremented once per spin_loop execution. - sx rw-lock stats: sx locks increments spin_loop counter but instead of incrementing it once for a spin_loop invocation it does it multiple times based on how many time spin_loop flow is repeated for same instance post os-wait. |
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| sync0arr.cc | ||
| sync0debug.cc | ||
| sync0rw.cc | ||
| sync0sync.cc | ||