The tw_timer implementation is extremely fast. We routinely test it to 60 million concurrent timers, the number required to bring up 10M TCP sessions.
Given a 500ms granularity, we have: max range = 86400 (secs/day) * 2 (clock ticks/second) = 172800 slots. A 2-ring, 512 slots/ring geometry would work. You can #include <vppinfra/tw_timer_16t_2w_512sl.h> and use that wheel geometry verbatim, so long as each object needs at most 16 independent timers. Look at .../src/vppinfra/test_tw_timer.c for an example which using this specific ring geometry. It’s the “double_wheel” test-case. You’ll probably need/want to add either a process node which wakes up every half second to run the tw_timer wheel, or an input node. Unless you have super-high perf / scale targets, go with the process node. HTH... Dave From: [email protected] <[email protected]> On Behalf Of Andreas Schultz Sent: Monday, August 13, 2018 11:54 AM To: [email protected] Subject: [vpp-dev] timing_wheel or tw_timer Hi, I need to implement per session timers with about 500ms granularity. Maximum timer range can be up to 24 hours. Should I use the timing_wheel (like BFD does) or one of the tw_timer's? And what is main difference between the timing_wheel and the tw_timer anyway? Thanks Andreas -- -- Dipl.-Inform. Andreas Schultz ----------------------- enabling your networks ---------------------- Travelping GmbH Phone: +49-391-81 90 99 0 Roentgenstr. 13 Fax: +49-391-81 90 99 299 39108 Magdeburg Email: [email protected]<mailto:[email protected]> GERMANY Web: http://www.travelping.com Company Registration: Amtsgericht Stendal Reg No.: HRB 10578 Geschaeftsfuehrer: Holger Winkelmann VAT ID No.: DE236673780 ---------------------------------------------------------------------
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