diff options
Diffstat (limited to 'erts/emulator/internal_doc')
| -rw-r--r-- | erts/emulator/internal_doc/CarrierMigration.md | 19 | ||||
| -rw-r--r-- | erts/emulator/internal_doc/CountingInstructions.md | 53 |
2 files changed, 56 insertions, 16 deletions
diff --git a/erts/emulator/internal_doc/CarrierMigration.md b/erts/emulator/internal_doc/CarrierMigration.md index 3a796d11b7..bb3d8aac28 100644 --- a/erts/emulator/internal_doc/CarrierMigration.md +++ b/erts/emulator/internal_doc/CarrierMigration.md @@ -34,8 +34,7 @@ Solution -------- In order to prevent scenarios like this we've implemented support for -migration of multi-block carriers between allocator instances of the -same type. +migration of multi-block carriers between allocator instances. ### Management of Free Blocks ### @@ -130,10 +129,6 @@ threads may have references to it via the pool. ### Migration ### -There exists one pool for each allocator type enabling migration of -carriers between scheduler specific allocator instances of the same -allocator type. - Each allocator instance keeps track of the current utilization of its multi-block carriers. When the total utilization falls below the "abandon carrier utilization limit" it starts to inspect the utilization of the @@ -208,8 +203,8 @@ limited. We only inspect a limited number of carriers. If none of those carriers had a free block large enough to satisfy the allocation request, the search will fail. A carrier in the pool can also be BUSY if another thread is currently doing block deallocation work on the -carrier. A BUSY carrier will also be skipped by the search as it can -not satisfy the request. The pool is lock-free and we do not want to +carrier. A BUSY carrier will also be skipped by the search as it cannot +satisfy the request. The pool is lock-free and we do not want to block, waiting for the other thread to finish. ### The bad cluster problem ### @@ -287,11 +282,3 @@ reduced using the `aoffcbf` strategy. A trade off between memory consumption and performance is however inevitable, and it is up to the user to decide what is most important. -Further work ------------- - -It would be quite easy to extend this to allow migration of multi-block -carriers between all allocator types. More or less the only obstacle -is maintenance of the statistics information. - - diff --git a/erts/emulator/internal_doc/CountingInstructions.md b/erts/emulator/internal_doc/CountingInstructions.md new file mode 100644 index 0000000000..d4b1213d00 --- /dev/null +++ b/erts/emulator/internal_doc/CountingInstructions.md @@ -0,0 +1,53 @@ +Counting Instructions +===================== + +Here is an example that shows how to count how many times each +instruction is executed: + + $ (cd erts/emulator && make icount) + MAKE icount + make[1]: Entering directory `/home/uabbgus/otp/erts/emulator' + . + . + . + make[1]: Leaving directory `/home/uabbgus/otp/erts/emulator' + $ cat t.erl + -module(t). + -compile([export_all,nowarn_export_all]). + + count() -> + erts_debug:ic(fun benchmark/0). + + benchmark() -> + %% Run dialyzer. + Root = code:root_dir(), + Wc1 = filename:join(Root, "lib/{kernel,stdlib}/ebin/*.beam"), + Wc2 = filename:join(Root, "erts/preloaded/ebin/*.beam"), + Files = filelib:wildcard(Wc1) ++ filelib:wildcard(Wc2), + Opts = [{analysis_type,plt_build},{files,Files},{get_warnings,true}], + dialyzer:run(Opts). + $ $ERL_TOP/bin/cerl -icount + Erlang/OTP 22 [RELEASE CANDIDATE 1] [erts-10.2.4] [source-ac0d451] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe] [instruction-counting] + + Eshell V10.2.4 (abort with ^G) + 1> c(t). + {ok,t} + 2> t:count(). + 0 badarg_j + 0 badmatch_x + 0 bs_add_jsstx + 0 bs_context_to_binary_x + . + . + . + 536461394 move_call_last_yfQ + 552405176 allocate_tt + 619920327 i_is_eq_exact_immed_frc + 636419163 is_nonempty_list_allocate_frtt + 641859278 i_get_tuple_element_xPx + 678196718 move_return_c + 786289914 is_tagged_tuple_frAa + 865826424 i_call_f + Total: 20728870321 + [] + 3> |