“professional programmer” • Got interested in Garbage Collection because I used Ruby professionally • This meetup is basically my dream come true Monday, February 24, 14 - A little bit about me
it routinely allocates memory from the heap. If more memory than available is needed, the collector reclaims unused memory and returns it to the heap.” Monday, February 24, 14 - And a definition
be its fundamental advantage. However, the cost of updating reference counts every time a new pointer is loaded into a register is typically much to high for high- performance applications.” Reference Counting Monday, February 24, 14 - Description
used...the result is delayed collection, floating garbage, and longer pauses - the typical characteristics of tracing collectors!” Reference Counting Monday, February 24, 14 - RC
the natural collection of cyclic garbage. However, a fundamental disadvantage of tracing is that freeing of dead objects is delayed...resulting in long pause times.” Mark & Sweep Monday, February 24, 14 - M&S
generational collection. This reduces the average pause time...but also introduces per-mutation overhead -- thus it takes on both some of the positive and negative aspects of reference counting collection.” Mark & Sweep Monday, February 24, 14 - M&S
• Hybrid Collectors • Cycle Collection • Multi-Heap Collectors • Cost Analysis • Space-Time Tradeoffs Monday, February 24, 14 - Formal framework - Fixed point formulation - Shows that what we think is different is similar
Breaks down cargo-culted beliefs • Nearly all production GCs are hybrids • Design recommendations Monday, February 24, 14 - Formal framework - Fixed point formulation - Shows that what we think is different is similar
optimized forms of reference counting and tracing collectors led directly to a deeper study of the algorithms in the hope of funding fundamental similarities that seem to be appearing in practice." Monday, February 24, 14 - Awesome quote
operates on dead objects, or 'anti- matter'. For every operation performed by the tracing collector, there is a precisely corresponding anti- operation performed by the reference counting collector.” Monday, February 24, 14 - Awesome quote
of focus for design • Really neat and novel Monday, February 24, 14 - Tradeoffs - algorithms which are good for distributed or disk backed systems would be terrible for VMs and vice versa - Authors provide a list of properties of GC algorithms which should be considered in design