bneradt commented on PR #13806: URL: https://github.com/apache/trafficserver/pull/13806#issuecomment-6198998139
We tried this in production. I cherry-picked the commit onto our 10.2.x-based build and compared two identical hosts in the same pod: same hardware, same traffic mix, `server_session_sharing.pool: global`. One ran the stock build and the other the same build plus this patch. Both were restarted within 16 seconds of each other. A window here is a 60-second interval in which we read each counter at the start and end on both hosts at the same moment, then divided the increase by the requests served in that interval. Per-request counters over 8 such paired windows, starting about an hour after the restarts, stock → patched: | Metric | Change | Windows lower | |---|---|---| | `origin_shutdown.pool_lock_contention` | −14% | 8 of 8 | | `origin.reuse_fail` | −14% | 8 of 8 | | `total_server_connections` (new origin connections) | −8% | 8 of 8 | In the access log, the share of origin requests that went out on an already-open connection rose from 75.0% to 76.8%, higher in all four 15-minute windows from the first hour after the restarts. Before the patch, with both hosts on the same build, the patched host actually opened slightly *more* origin connections than its partner. So the improvement isn't a quirk of that host. Client TTFB, origin wait, 5xx share and cache hit ratio didn't change outside noise. ATS CPU per request read about 3% lower on the patched host, but we have no same-build baseline for that window, so I wouldn't read anything into it in either direction. For comparison, you saw about 2% higher CPU with the patch. Stability: no crashes or restarts over about 1.5 hours in rotation, and `origin_shutdown.migration_failure` stayed at 0 throughout. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
