socket: amortise cost of querying OS time counter#149
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#116 adds a much needed ability to shrink the connection pool, but requires tracking the last-used timestamp for each socket after every operation. Frequent calls to time.Now() in the hot-path reduced read throughput by ~6% and increased the latency (and variance) of socket operations as a whole. This PR adds a periodically updated time value to amortise the cost of the last- used bookkeeping, restoring the original throughput at the cost of approximate last-used values (configured to be ~25ms of potential skew). On some systems (currently including FreeBSD) querying the time counter also requires a syscall/context switch. Fixes #142.
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globalsign#116 adds a much needed ability to shrink the connection pool, but requires tracking the last-used timestamp for each socket after every operation. Frequent calls to time.Now() in the hot-path reduced read throughput by ~6% and increased the latency (and variance) of socket operations as a whole. This PR adds a periodically updated time value to amortise the cost of the last- used bookkeeping, restoring the original throughput at the cost of approximate last-used values (configured to be ~25ms of potential skew). On some systems (currently including FreeBSD) querying the time counter also requires a syscall/context switch. Fixes globalsign#142.
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#116 adds a much needed ability to shrink the connection pool, but requires
tracking the last-used timestamp for each socket after every operation. Frequent
calls to time.Now() in the hot-path reduced read throughput by ~6% and increased
the latency (and variance) of socket operations as a whole.
This PR adds a periodically updated time value to amortise the cost of the last-
used bookkeeping, restoring the original throughput at the cost of approximate
last-used values (configured to be ~25ms of potential skew).
On some systems (currently including FreeBSD) querying the time counter also
requires a syscall/context switch.
Fixes #142.