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2019-05-06Merge branch 'maint'Sverker Eriksson
2019-05-06Merge branch 'sverker/process_info-reductions-fix/OTP-15793' into maintSverker Eriksson
* sverker/process_info-reductions-fix/OTP-15793: erts: Force process_info(reductions) as signal erts: Fix another bug in process_info(reductions)
2019-05-03erts: Force process_info(reductions) as signalSverker Eriksson
Not 100% sure this is needed to get correct reductions as the direct query is not done if process is RUNNING anyway.
2019-04-18Merge branch 'rickard/dist-system-limit/OTP-15708'Rickard Green
* rickard/dist-system-limit/OTP-15708: Fail when we cannot encode term in binary
2019-04-18Fix broken ETS test caseKjell Winblad
This commit fixes an ETS test case that tests the decentralized memory counter in tables of type ordered_set with the write_concurrency option turned on. The test case assumed that the memory consumption of the table would only grow monotonically when terms are inserted. However, this was not the case when the emulator was compiled in debug mode as random splits and joins of CA tree nodes could happen. This commit fixes the test case by disabling random splits and joins in the tested table.
2019-04-11Merge branch 'sverker/revert-big-creation'Sverker Eriksson
* sverker/revert-big-creation: Revert "erts: Make DFLAG_BIG_CREATION mandatory" Revert "erts: Remove old encoding of pids, ports and refs" Revert "erl_interface: Remove old encoding of pid,port,refs" Revert "epmd: Support 32-bit creation values in local node" Revert "jinterface: Remove old encoding of pid,port,refs" Revert "erl_interface: Support 32-bit creation local cnode" Revert "erts: Document new EPMD response ALIVE2_X_RESP"
2019-04-10Decentralized counters for ETS ordered_set with write_concurrencyKjell Winblad
Previously, all ETS tables used centralized counter variables to keep track of the number of items stored and the amount of memory consumed. These counters can cause scalability problems (especially on big NUMA systems). This commit adds an implementation of a decentralized counter and modifies the implementation of ETS so that ETS tables of type ordered_set with write_concurrency enabled use the decentralized counter. [Experiments][1] indicate that this change substantially improves the scalability of ETS ordered_set tables with write_concurrency enabled in scenarios with frequent `ets:insert/2` and `ets:delete/2` calls. The new counter is implemented in the module erts_flxctr (`erts_flxctr.h` and `erts_flxctr.c`). The module has the suffix flxctr as it contains the implementation of a flexible counter (i.e., counter instances can be configured to be either centralized or decentralized). Counters that are configured to be centralized are implemented with a single counter variable which is modified with atomic operations. Decentralized counters are spread over several cache lines (how many can be configured with the parameter `+dcg`). The scheduler threads are mapped to cache lines so that there is no single point of contention when decentralized counters are updated. The thread progress functionality of the Erlang VM is utilized to implement support for linearizable snapshots of decentralized counters. The snapshot functionality is used by the `ets:info/1` and `ets:info/2` functions. [1]: http://winsh.me/ets_catree_benchmark/flxctr_res.html
2019-04-09Revert "epmd: Support 32-bit creation values in local node"Sverker Eriksson
This reverts commit bd8f6106d44a58c261920eef72842bb3bc5a4968. PLUS a little change in epmd_srv.c:750 ("4" -> "replylen") that was part of e2cf4a8a4b03b9f430ba228276c3b2629159e832 by mistake.
2019-04-09erts: Fix lock order violation in system_info(procs)Lukas Larsson
2019-04-05Fail when we cannot encode term in binaryRickard Green
Fail when we cannot encode term in binary instead of producing a faulty result.
2019-03-25erts: Fix erts_debug:set_internal_state(reds_left)Sverker Eriksson
to avoid failed ERTS_DBG_CHK_REDS by clearing virtual_reds.
2019-03-22Merge branch 'sverker/enable-big-creation/OTP-15603'Sverker Eriksson
* sverker/enable-big-creation/OTP-15603: epmd: Support 32-bit creation values in local node erts: Robustify epmd reply function erts: Reject decoded local refs with too large first word erts: Fix bug in list_to_ref erl_interface: Remove old encoding of pid,port,refs erts: Remove old encoding of pids, ports and refs erts: Make DFLAG_BIG_CREATION mandatory
2019-03-22epmd: Support 32-bit creation values in local nodeSverker Eriksson
* Increase distribution version from 5 to 6 * Introduce new ALIVE2_X_RESP with 32-bit creation as reply to ALIVE2_REQ when sender dist version >= 6 * Still reply old ALIVE2_RESP with tiny creation 1..3 if sender dist version < 6.
2019-03-19Merge branch 'sverker/enif_whereis_pid-dirty-dtor'Sverker Eriksson
into sverker/master/enif_whereis_pid-dirty-dtor
2019-03-19erts: Schedule resource destructors alwaysSverker Eriksson
to run user NIF code in a more known execution context. Fixes problems like user calling enif_whereis_pid() in destructor which may need to release process main lock in order to lock reg_tab.
2019-03-07Merge branch 'sverker/maint/ets-no-mbuf-trapping/OTP-15660'Sverker Eriksson
into sverker/master/ets-no-mbuf-trapping/OTP-15660
2019-03-07Merge branch 'sverker/ets-no-mbuf-trapping/OTP-15660'Sverker Eriksson
into sverker/maint/ets-no-mbuf-trapping/OTP-15660
2019-03-07erts: Remove ets traversal yielding if heap fragmentSverker Eriksson
Many heap fragments do no longer make the GC slow. Even worse, we are not guaranteed that a yield will provoke a GC removing the fragments, which might lead to a one-yield-per-bucket scenario if the heap fragment(s) still remains after each yield.
2019-02-05erts: Refactor rbt _yielding to use reductionsLukas Larsson
All of the Red-Black Tree _yielding functions have been updated to work with reductions returned by the called function instead of yielding on each element.
2019-02-01Merge branch 'maint'Lukas Larsson
2019-02-01erts: Fix erlang:system_info(kernel_poll) to return correct valueLukas Larsson
2019-01-15Merge branch 'maint'Lukas Larsson
2019-01-15erts: Make sure to take main lock when dumping proc infoLukas Larsson
If the main lock is not taken then any process running on a dirty scheduler may cause all kinds of problems.
2019-01-15Merge branch 'maint'Lukas Larsson
Conflicts: erts/emulator/beam/bif.c erts/preloaded/ebin/erlang.beam erts/preloaded/ebin/erts_internal.beam erts/preloaded/ebin/prim_file.beam
2019-01-10erts: Add erlang:system_flag(system_logger,_)Lukas Larsson
This flag allows logger and other components to set the process which log messages from ERTS are to be sent.
2018-10-23erts: Add erts_debug feature 'ets_force_split'Sverker Eriksson
to easier generate a routing tree for test without having to spend cpu to provoke actual repeated lock conflicts.
2018-09-07erts: Beautify away #ifdef DEBUGSverker Eriksson
"(void)result" will silence warning about unused variable and compiler will optimize away such unused variables.
2018-07-18erts: Remove use of VALGRIND_PRINTF_XMLSverker Eriksson
which only existed in a patched version of valgrind (by pan) no longer used. Instead we use standard VALGRIND_PRINTF which will end up like this if valgrind log format is XML and valgrind version >= 3.9: <clientmsg> <tid>7</tid> <threadname>3_scheduler</threadname> <text>Test case #20 ei_encode_SUITE:test_ei_encode_long/1 </text> </clientmsg> Note the extra trailing whitespace that may occure before </text>.
2018-07-10erts: Fix buggy calls to erts_sys_explicit_8bit_getenvSverker Eriksson
Two of them only affect valgrind builds and the one for ERL_CRASH_DUMP_NICE seems benign. Return value changed in c2d70945dce9cb09d5d7120d6e9ddf7faac8d230 old -> new -1 -> 0 not found 0 -> 1 found ok 1 -> -1 found but too big
2018-06-04erts: Add system_info(ets_count)Sverker Eriksson
2018-05-18Merge branch 'sverker/ets-delete_all_objects-trap/OTP-15078'Sverker Eriksson
* sverker/ets-delete_all_objects-trap/OTP-15078: erts: Rename untrapping db_free_*empty*_table erts: Make ets:delete_all_objects yield on fixed table erts: Optimize ets delete all in fixed table erts: Refactor ets select iteration code erts: Cleanup ets code erts: Optimize ets hash object deallocactions erts: Refactor pseudo deleted ets objects erts: Make atomic ets:delete_all_objects yield erts: Fix reduction bump for ets:delete/1
2018-05-16Fix erts_try_lock_sig_free_proc()Rickard Green
2018-05-16New process suspend implementation based on async signalingRickard Green
2018-05-08erts: Make atomic ets:delete_all_objects yieldSverker Eriksson
by using a cooperative strategy that will make any process accessing the table execute delelete_all_objects_continue until the table is empty. This is not an optimal solution as concurrent threads will still block on the table lock, but at least thread progress is made.
2018-04-27Merge branch 'rickard/process_info/OTP-14966'Rickard Green
* rickard/process_info/OTP-14966: Fix scheduled process_info() 'status' request Fix handling of process-info requests in receive
2018-04-26Fix handling of process-info requests in receiveRickard Green
2018-04-24Merge pull request #1790 from jhogberg/john/erts/more-alloc-info/OTP-14961John Högberg
Improve memory instrumentation OTP-15024 OTP-14961
2018-04-23erts: Rewrite memory instrumentationJohn Högberg
This commit replaces the old memory instrumentation with a new implementation that scans carriers instead of wrapping erts_alloc/erts_free. The old implementation could not extract information without halting the emulator, had considerable runtime overhead, and the memory maps it produced were noisy and lacked critical information. Since the new implementation walks through existing data structures there's no longer a need to start the emulator with special flags to get information about carrier utilization/fragmentation. Memory fragmentation is also easier to diagnose as it's presented on a per-carrier basis which eliminates the need to account for "holes" between mmap segments. To help track allocations, each allocation can now be tagged with what it is and who allocated it at the cost of one extra word per allocation. This is controlled on a per-allocator basis with the +M<S>atags option, and is enabled by default for binary_alloc and driver_alloc (which is also used by NIFs).
2018-04-18Merge branch 'sverker/lock-check-matrix'Sverker Eriksson
2018-04-13erts: Add erts_debug:lc_graph/0Sverker Eriksson
Run debug VM or config with --enable-lock-checking. Exercise VM and then run erts_debug:lc_graph(). to create a file "lc_graph.<pid>" in current working directory.
2018-04-12New process_info() implementation using signalsRickard Green
2018-03-23Merge branch 'rickard/signals/OTP-14589'Rickard Green
* rickard/signals/OTP-14589: Fix VM probes compilation Fix lock counting Fix signal order for is_process_alive Fix signal handling priority elevation
2018-03-22Fix signal order for is_process_aliveRickard Green
2018-03-21Merge pull request #1740 from rickard-green/rickard/signals/OTP-14589Rickard Green
Implementation of true asynchronous signaling between processes
2018-03-21Implementation of true asynchronous signaling between processesRickard Green
Communication between Erlang processes has conceptually always been performed through asynchronous signaling. The runtime system implementation has however previously preformed most operation synchronously. In a system with only one true thread of execution, this is not problematic (often the opposite). In a system with multiple threads of execution (as current runtime system implementation with SMP support) it becomes problematic. This since it often involves locking of structures when updating them which in turn cause resource contention. Utilizing true asynchronous communication often avoids these resource contention issues. The case that triggered this change was contention on the link lock due to frequent updates of the monitor trees during communication with a frequently used server. The signal order delivery guarantees of the language makes it hard to change the implementation of only some signals to use true asynchronous signaling. Therefore the implementations of (almost) all signals have been changed. Currently the following signals have been implemented as true asynchronous signals: - Message signals - Exit signals - Monitor signals - Demonitor signals - Monitor triggered signals (DOWN, CHANGE, etc) - Link signals - Unlink signals - Group leader signals All of the above already defined as asynchronous signals in the language. The implementation of messages signals was quite asynchronous to begin with, but had quite strict delivery constraints due to the ordering guarantees of signals between a pair of processes. The previously used message queue partitioned into two halves has been replaced by a more general signal queue partitioned into three parts that service all kinds of signals. More details regarding the signal queue can be found in comments in the erl_proc_sig_queue.h file. The monitor and link implementations have also been completely replaced in order to fit the new asynchronous signaling implementation as good as possible. More details regarding the new monitor and link implementations can be found in the erl_monitor_link.h file.
2018-03-16mikpe/process_info-1-no-messages/PR-1745/OTP-14986Lukas Larsson
make erlang:process_info/1 not retrieve messages
2018-03-10make erlang:process_info/1 not retrieve messagesMikael Pettersson
process_info/1 retrieves a number of properties related to a process, including the list of messages in its mailbox. This is potentially unsafe if the target process has a large number of queued messages: - there is no a priori upper bound on the amount of memory being allocated to hold that list, and - the loop to retrieve the messages is uninterruptible, so the Erlang scheduler where this executes blocks for the duration We've seen process_info/1 bring down heavily loaded nodes on more than one occasion. At least once it appeared to have blocked the Erlang heart process from executing, causing the external heart to kill the VM. Consequently this removes 'messages' from the list of process_info tags to retrieve for process_info/1. Note that process_info/1 still retrieves 'message_queue_len', and process_info/2 can still retrieve 'messages' when asked to. A few places in the OTP libraries need minor adjustments, since they want 'message_queue_len' but compute it from the length of the list of messages.
2018-03-09Always use sys_memcpy/cmp/etc instead of plain memcpy/cmp/etcJohn Högberg
2018-01-15Merge branch 'maint'Sverker Eriksson
2018-01-08Merge branch 'john/erts/putenv-thread-safety/OTP-14666'John Högberg