Replace allocations count by GC time in request logs #51770
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Allocations count is often an interesting proxy for performance, but not necessarily the most relevant thing to include in request logs, given they aren't a per thread metric, so the reporting is widely innacurate in multi-threaded environments. Since Ruby 3.1 there is now `GC.total_time` which is a monotonically increasing counter of time spent in GC. It still isn't really a per thread metric, but is is more interesting because it uses the same unit as the response time, allowing to better see when you have a GC pause performance issue.
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Allocations count is often an interesting proxy for performance, but not necessarily the most relevant thing to include in request logs, given they aren't a per thread metric, so the reporting is widely innacurate in multi-threaded environments.
Since Ruby 3.1 there is now
GC.total_timewhich is a monotonically increasing counter of time spent in GC. It still isn't really a per thread metric, but is is more interesting because it uses the same unit as the response time, allowing to better see when you have a GC pause performance issue.