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| author | Björn Gustavsson <[email protected]> | 2018-12-06 13:07:42 +0100 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2018-12-18 11:40:07 +0100 |
| commit | 1ea57e5498d92b730644cb37b659d16e51f56b4d (patch) | |
| tree | 3464aa1912825e297d0609abe0af8b3eeb1af315 /erts/emulator/beam/erl_vm.h | |
| parent | 472b0669788e155f28851999b4e60bf8302ca2d5 (diff) | |
| download | otp-1ea57e5498d92b730644cb37b659d16e51f56b4d.tar.gz otp-1ea57e5498d92b730644cb37b659d16e51f56b4d.tar.bz2 otp-1ea57e5498d92b730644cb37b659d16e51f56b4d.zip | |
Make length/1 yielding
The guard BIF `length/1` would calculate the length of the list in one
go without yielding, even if the list was were long. To make it even
worse, the call to `length/1` would only cost a single reduction.
This commit reimplements `length/1` so that it eats a number of
reductions proportional to the length of the list, and yields if the
available reductions run out.
Diffstat (limited to 'erts/emulator/beam/erl_vm.h')
| -rw-r--r-- | erts/emulator/beam/erl_vm.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/erts/emulator/beam/erl_vm.h b/erts/emulator/beam/erl_vm.h index fd46a804d3..35eae18394 100644 --- a/erts/emulator/beam/erl_vm.h +++ b/erts/emulator/beam/erl_vm.h @@ -41,8 +41,8 @@ #define MAX_REG 1024 /* Max number of x(N) registers used */ /* - * The new arithmetic operations need some extra X registers in the register array. - * so does the gc_bif's (i_gc_bif3 need 3 extra). + * The new trapping length/1 implementation need 3 extra registers in the + * register array. */ #define ERTS_X_REGS_ALLOCATED (MAX_REG+3) |