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2012-03-22Add DTrace support for OS X, Solaris, and Linux (via SystemTap), 1/4Scott Lystig Fritchie
Since it's been quite a while since I've written C code, *and* I haven't done any significant hacking on the VM itself in years, it's quite likely that I haven't done things in 100% proper style. Or my co-collaborators Dustin Sallings (CouchBase) or Michal Ptaszek (Erlang Solutions). My intent for this patch is to start discussion and review of DTrace support for consideration for the R15 release. For additional background on the motivation for this work, please see the slides for the presentation at the Erlang User Conference 2011 in Stockholm: https://www.erlang-factory.com/upload/presentations/462/euc2011-draft2.pdf Changes relative to dtrace-review2 branch: * Fix errors in OTP test suite 'kernel' file_SUITE * Fix errors in OTP test suite 'kernel' prim_file_SUITE * Fix bad pointer bug in efile_drv.c flush_write() * Move the DTrace material from the top of `README.md` into a new file, `README.dtrace.md` Changes since last push to GitHub (relative to commit 5828a4fb28, which was the former `dtrace-review1` branch): * Rebased onto 14 Nov 2011's "master" branch * Recent changes to the async task queuing mechanism means that the async worker queue length is not available. A bogus value of -1 is hard-coded until there's a good way to peek into the new queue structure and find the queue length. * Small fixes based on review comments by Mikael Pettersson, Andrew Thompson, and Andreas Schultz. Add autoconf support: use "./configure --enable-dtrace" on all supported platforms: * OS X Snow Leopard or later * Solaris 10 or OpenSolaris * Linux, via SystemTap's DTrace compatibility packages * FreeBSD 9.0RC1. FreeBSD 8 and earlier do not have support for USDT, DTrace's User-land Statically Defined Tracing. See the file `erts/emulator/beam/erlang_dtrace.d` for the definition of all DTrace probes in the virtual machine so far. Example D scripts can be found in `lib/dtrace/examples`. Note that if you see the error message `{name of probe} does not match any probes`, then there is no Erlang VM process + DTrace probes running. To fix, start a DTrace-enabled VM or remove `-q` from the `dtrace` command line. The `lib/dtrace` directory contains a small code-only OTP application that contains code that allows Erlang code to trigger a DTrace probe. Dynamic creation & deletion of DTrace probes is not currently supported, so the `dtrace:p()` function is hacked to allow a variable number of arguments (up to four integers and up to four strings) to be used. See the comments at the top of `lib/dtrace/src/dtrace.c` for more detail. One feature that may be controversial is the notion I've introduced of a special process dictionary key that can be used by Erlang code to tag I/O operations for an application-specific purpose. Right now, that tag's name is `dtrace_utag`. The dictionary keys used by `sys` and other modules start with a dollar sign. Perhaps there is some convention (but not a dollar sign?) that this tag should use? The purpose of the process dictionary key is to allow the tag to be included in trace messages, e.g. for file I/O, without changing the API of the `file.erl` module's functions. For example, here's a use of the tag when calling the `file:rename/2` function: (bar@sbb2)1> put(dtrace_utag, "GGOOOAAALL!!!!!"). undefined (bar@sbb2)2> dtrace:init(). ok %% Now start both the `user-probe.d` and `efile_drv.d` D scripts %% found in the `lib/dtrace/examples` directory. (bar@sbb2)3> dtrace:p(7, 8, 9, "one", "four"). true %% The output from the `user-probe.d` script: <0.40.0> GGOOOAAALL!!!!! 7 8 9 0 'one' 'four' '' '' (bar@sbb2)4> file:rename("old-name", "new-name"). {error,enoent} %% The output from the `efile_drv.d` script: async I/O pool port #Port<0.59> queue len 1 async I/O pool port #Port<0.59> queue len 0 efile_drv enter tag={1,110} user tag GGOOOAAALL!!!!! | RENAME (12) | args: old-name new-name , 0 0 (port #Port<0.59>) async I/O worker tag={1,110} | RENAME (12) | efile_drv-int_entry async I/O worker tag={1,110} | RENAME (12) | efile_drv-int_return efile_drv return tag={1,110} user tag GGOOOAAALL!!!!! | RENAME (12) | errno 2 I'm not exactly happy with this choice of tagging, namely using `put(dtrace_utag, Tag::list())`. But this is an experiment, so we'll see how it goes. I can't imagine changing the API for all file.erl functions in order pass the tag explicitly. Some modules have some extensive (ab)use of the C preprocessor to reduce the amount of #ifdefs that clutter the code. In several places, I have not #ifdef'ed automatic variables because of clutter. For the same reason, there are a handful of cases where I added DTrace-related members to a struct definition without an #ifdef. I feel that the result is easier to read than earlier drafts where I did use many more `https://github.com/slfritchie/otp/tree/dtrace-experiment+michal2` if you're curious.) I expect there may be some debate about whether the bloat of the affected structs is worthwhile. I erred on adding stuff to structs, especially in the efile_drv.c driver, not having a full grasp on what was thread-safe and what was not ... so I erred on the side of caution. The efile_drv.c has a work-around for a crazy GCC optimization bug. Thank goodness for Google, I dunno how I would've found a work-around for this silly thing. Many thanks to Trond Norbye for writing clearly about the problem in a membase Git repo commit message. /* * A note on probe naming: if "__" appears in a provider probe * definition, then two things happen during compilation: * * 1. The "__" will turn into a hypen, "-", for the probe name. * 2. The "__" will turn into a single underscore, "_", for the * macro names and function definitions that the compiler and * C developers will see. * * We'll try to use the following naming convention. We're a bit * limited because, as a USDT probe, we can only specify the 4th part * of the probe name, e.g. erlang*:::mumble. The 2nd part of the * probe name is always going to be "beam" or "beam.smp", and the 3rd * part of the probe name will always be the name of the function * that's calling the probe. * * So, all probes will be have names defined in this file using the * convention category__name or category__sub_category__name. This * will translate to probe names of category-name or * category-sub_category-name. * * Each of "category", "sub_category", and "name" may have underscores * but may not have hyphens. */ Add tentative support for sequential tracing sending, queueing, and receiving a message. I don't believe I've fully covered all the major places where it would be useful to have the sequential trace token info in a probe -- guidance from the OTP team would be helpful, if there's time to do that kind of review. Add global variable `erts_this_node_sysname`.
2012-03-21erts: Remove forgotten and unused function erl_exit0Raimo Niskanen
2012-03-21erts: Implement erl_haltRaimo Niskanen
2011-12-09erl_driver.h: Enlarge type on return value from callRaimo Niskanen
2011-12-09erl_driver.h: Enlarge types on driver callbacks output, control and callRaimo Niskanen
2011-12-07erl_driver.h: Enlarge types in driver output functionsRaimo Niskanen
2011-12-07erl_driver.h: Use ErlDrvSizeT for size field in ErlIOVecRaimo Niskanen
2011-12-02Iron out bugs in Win64 found in daily buildsPatrik Nyblom
Almost all uses of the 'long' datatype is removed from VM and tests Emulator test now runs w/o drivers crashing Nasty abs bug fixed in VM as well as type errors in allocator debug functions Still one allocator test that fails, domain knowledge is needed to fix that. Fix type inconsistency in beam_load causing crashes
2011-12-02Get working prompt in Win64 using bootstrap codePatrik Nyblom
2011-12-01Merge branch 'rickard/rm-common-runq/OTP-9727'Rickard Green
* rickard/rm-common-runq/OTP-9727: Remove common run-queue in SMP case Fix scheduler suspend bug Conflicts: erts/emulator/beam/erl_init.c
2011-12-01Remove common run-queue in SMP caseRickard Green
The common run-queue implementation is removed since it is unused, untested, undocumented, unsupported, and only complicates the code. A spinlock used by the run-queue management sometimes got heavily contended. This code has now been rewritten, and the spinlock has been removed.
2011-11-17Allow refc binaries in literal poolsBjörn Gustavsson
To simplify the implementation of literal pools (constant pools) for the R12 release, a shortcut was taken regarding binaries -- all binaries would be stored as heap binaries regardless of size. To allow a module containing literals to be unloaded, literal terms are copied when sent to another process. That means that huge literal binaries will also be copied if they are sent to another process, which could be surprising. Another problem is that the arity field in the header for the heap object may not be wide enough to handle big binaries. Therefore, bite the bullet and allow refc binaries to be stored in literal pools. In short, the following need to be changed: * Each loaded module needs a MSO list, linking all refc binaries in the literal pool. * When check_process_code/2 copies literals to a process heap, it must link each referenced binary into the MSO list for the process and increment the reference counter for the binary. * purge_module/1 must decrement the reference counter for each refc binary in the literal pool.
2011-11-14BEAM loader: Refactor code loading into separate functionsBjörn Gustavsson
Break apart code loading into the three functions: erts_alloc_loader_state() erts_prepare_loading() erts_finish_loading() The erts_alloc_loader_state() and erts_prepare_loading() can be executed with all schedulers running. Only erts_finish_loading() needs to be run in a single-scheduling system.
2011-11-14BEAM loader: Clean up handling of error reasonsBjörn Gustavsson
There is no reason to have erts_load_module() return integer values, only to have the caller convert the values to atoms. Return the appropriate atom directly from the place where the error is generated instead. Return NIL if the module was successfully loaded.
2011-11-14Remove the useless -l optionBjörn Gustavsson
The -l option used to print information about modules being loaded, but now it prints very little information.
2011-11-13Merge branch 'rickard/generic-thr-queue/OTP-9632'Rickard Green
* rickard/generic-thr-queue/OTP-9632: Use generic lock-free queue for async threads Use generic lock-free queue for misc aux work Implement generic lock-free queue
2011-11-13Merge branch 'rickard/alloc-opt/OTP-7775'Rickard Green
* rickard/alloc-opt/OTP-7775: Optimize memory allocation Conflicts: erts/aclocal.m4 erts/emulator/hipe/hipe_bif_list.m4 erts/preloaded/ebin/erl_prim_loader.beam erts/preloaded/ebin/erlang.beam erts/preloaded/ebin/init.beam erts/preloaded/ebin/otp_ring0.beam erts/preloaded/ebin/prim_file.beam erts/preloaded/ebin/prim_inet.beam erts/preloaded/ebin/prim_zip.beam erts/preloaded/ebin/zlib.beam
2011-11-13Use generic lock-free queue for async threadsRickard Green
Queues used for communication between async threads and scheduler threads have been replaced with lock-free queues. Drivers using the driver_async functionality are not automatically locked to the system anymore, and can be unloaded as any dynamically linked in driver. Scheduling of ready async jobs is now also interleaved in between other jobs. Previously all ready async jobs was performed at once.
2011-11-13Optimize memory allocationRickard Green
A number of memory allocation optimizations have been implemented. Most optimizations reduce contention caused by synchronization between threads during allocation and deallocation of memory. Most notably: * Synchronization of memory management in scheduler specific allocator instances has been rewritten to use lock-free synchronization. * Synchronization of memory management in scheduler specific pre-allocators has been rewritten to use lock-free synchronization. * The 'mseg_alloc' memory segment allocator now use scheduler specific instances instead of one instance. Apart from reducing contention this also ensures that memory allocators always create memory segments on the local NUMA node on a NUMA system.
2011-10-26Change the calling convention for BIFsBjörn Gustavsson
The current calling convention for BIFs makes it necessary to handle each arity specially, since each argument for the BIF also becomes an argument for the C function implementing the BIF, which makes it hard to allow BIFs with any number of arguments. Change the calling convention for BIFs, so that BIF arguments are passed in an array to the C function implementing the BIF.
2011-10-26Use the proper macros in all BIFsBjörn Gustavsson
As a preparation for changing the calling convention for BIFs, make sure that all BIFs use the macros. Also, eliminate all calls from one BIF to another, since that also breaks the calling convention abstraction.
2011-08-18erl: Add +L to suppress loading of line number informationBjörn Gustavsson
2011-08-16beam_emu: Factor out saving of stack trace from save_stacktrace()Björn Gustavsson
Put the actual saving of the continuation pointers on the stack in the new function erts_save_stacktrace() so that it can be reused. The code is too tricky and complicated to allow it to become duplicated.
2011-08-16Lookup and include filenames and line numbers in exceptionsBjörn Gustavsson
2011-08-16Refactor building of the exception stacktraceBjörn Gustavsson
As a preparation for providing information about the source location for an MFA item in an exception stacktrace, refactor the code that builds the exception stacktrace. Basically we need two passes over the saved continuation counters: a first pass to calculate the needed heap space and a second pass to actually build the stacktrace.
2011-06-14Use new atomic API in runtime systemRickard Green
All uses of the old deprecated atomic API in the runtime system have been replaced with the use of the new atomic API. In a lot of places this change imply a relaxation of memory barriers used.
2011-05-13Merge branch 'rickard/barriers/OTP-9281' into devRickard Green
* rickard/barriers/OTP-9281: Silence warnings Fix build with hipe on amd64 Reduce number of atomic ops Use 32-bit atomic for port snapshot Remove pointless erts_ports_alive variable Ensure quick break Ensure that all rehashing information are seen when done Ensure that stack updates are seen when stack is released Add needed barriers for write_concurrency tables Homogenize memory barriers on atomics
2011-05-13Use 32-bit atomic for port snapshotRickard Green
2011-05-13Remove pointless erts_ports_alive variableRickard Green
2011-05-13Merge branch 'bjorn/fix-warnings/OTP-9250' into devBjörn Gustavsson
* bjorn/fix-warnings/OTP-9250: Eliminate alias warning in gcc 4.5.2 erl_trace: Eliminate alias warning
2011-05-11erl_trace: Eliminate alias warningBjörn Gustavsson
Avoid creating two variable names referring to the same memory area, because that can cause aliasing warnings in some versions of gcc.
2011-05-10Replace io_list_len() with erts_iolist_size()Björn Gustavsson
The io_list_len() function returns an int, where a negative return value indicates a type error. One problem is that an int only consists of 32 bits in a 64-bit emulator. Changing the return type to Sint will solve that problem, but in the 32-bit emulator, a large iolist and a iolist with a type error will both return a negative number. (Noticed by Jon Meredith.) Another problem is that for iolists whose total size exceed the word size, the result would be truncated, leading to a subsequent buffer overflow and emulator crash. Therefore, introduce the new erts_iolist_size() function which returns a status indication and writes the result size through a passed pointer. If the result size does not fit in a word, return an overflow indication.
2011-03-16erts_printf %be to print integers of size EtermSverker Eriksson
Existing %bp to print pointer size integers does not work in halfword emulator to print Eterm size integers.
2011-03-11Merge branch 'bjorn/binary-overflow/OTP-9117' into devBjörn Gustavsson
* bjorn/binary-overflow/OTP-9117: Fix 18 exabyte memory allocation failure
2011-03-10Merge branch 'pg/fix-hibernate-with-hipe' into devSverker Eriksson
* pg/fix-hibernate-with-hipe: Update copyright years Fix NULL-free bug in hibernate on debug emulator Fix several bugs related to hibernate/3 and HiPE Conflicts: erts/emulator/test/hibernate_SUITE.erl OTP-9125
2011-03-09Fix 18 exabyte memory allocation failureBjörn Gustavsson
The new_binary() function takes a size argument that is an int. In the 64-bit emulator (sizeof(int) == 4, sizeof(Uint) == 8), any sizes >= 0x8000000 become 0xffffffff80000000 and above and triggers a memory allocation failure. Change the type of the size argument to Uint, and change any callers that cast the argument to an int. Correction-by: Jon Meredith
2011-02-03HALFWORD ETS Further match spec optimization to minimize copying and garbageSverker Eriksson
2011-02-03HALFWORD ETS Real matching on relative termsSverker Eriksson
2011-02-03HALFWORD ETS relative termsSverker Eriksson
In halfword emulator, make ETS use a variant of the internal term format that uses relative offsets instead of absolute pointers. This will allow storage in high memory (>4G). Preprocessor macros (like list_val_rel(TERM,BASE)) are used to make normal (fullword) emulator almost completely unchanged while still reusing most of the code.
2011-01-29Fix several bugs related to hibernate/3 and HiPEPaul Guyot
This commit fixes four related bugs: - calling hibernate/3 using a dynamic call would fail with badarg as hibernate/3 as a BIF was not implemented. hibernate/3 is generally provided as a Beam instruction, and code is translated to use this instruction when loaded. - calling hibernate/3 from HiPE would fail with badarg because this would call the aforementioned BIF which was not implemented. - calling hibernate/3 with some HiPE-native garbage in the process heap would randomly crash at the next garbage collect. This bug only happened in a complex, yet reproduceable scenarios, where native code calls beam code that calls hibernate/3, and the process has some garbage when being hibernated and the process generates garbage when awaken. - when entering HiPE, the process current_function can be set and be inaccurate. The fix is three folded: - hibernate_3 BIF now actually works instead of throwing a badarg. While hibernate_3 BIF was (usually) not called from BEAM, it is called from HiPE. hibernate behaviour is very close to the scheduler and this is why it is implemented as an instruction in BEAM. The fix consists in doing the actual hibernation (through the now exported erts_hibernate function) and setting the process flag to TRAP as well as the process status to P_WAITING. On BIF epilogue in both BEAM and HiPE, this status is tested on TRAP and if set, the scheduler is invoked. The i_hibernate instruction and translation code is now redundant and could be deleted. - hibernation now also empties the HiPE native stack, with a new function hipe_empty_nstack provided by Mikael Pettersson. - when entering HiPE through hipe_mode_switch, p->current is cleared, as suggested by Mikael Pettersson. p->current normally hold a pointer to the {M,F,A} of the current function if it exists. When hibernating, it is set to {erlang,hibernate,3}, and all stdlib hibernate tests (gen_server_SUITE:hibernate/1, proc_lib_suite:hibernate/1, etc.) actually rely on this information. Clearing p->current fixes the tests and avoids the surprise one might have when querying the process info of a process that hibernated and woke up in a native function. Non-regression tests are provided, a test for the dynamic call as well as a Makefile-handled duplication of the hibernate_SUITE into hibernate_native_SUITE for the HiPE case.
2010-12-20Refactor timer interfaceBjörn-Egil Dahlberg
2010-12-16Use 32-bit atomics for misc scheduling specific informationRickard Green
2010-12-15Use new atomic types in emulatorRickard Green
2010-11-30Teach spawn_executable about UnicodePatrik Nyblom
Also corrected compressed files on Windows
2010-11-30Convert filenames read on MacOSX to canonical formPatrik Nyblom
2010-11-22ETS 'compressed' option.Sverker Eriksson
The compressed format is using a slighty modified variant of the extern format (term_to_binary). To not worsen key lookup's too much, the top tuple itself and the key element are not compressed. Table objects with only immediate non-key elements will therefor not gain anything (but actually consume one extra word for "alloc_size").
2010-11-18Move cpu topology functionality into erl_cpu_topology.[ch]Rickard Green
2010-08-17erts: Remove stray pre-ISO-C compatibility macrosBjörn Gustavsson
A long time ago, the Erlang run-time system could be build with pre-ANSI/ISO-C (K&R) C compilers, but that is no longer possible. Remove the remaining uses of the compatibility macros that made it possible that possible.
2010-07-22Mending halfword heap emulatorSverker Eriksson
2010-07-20One off-heap list, to eliminate two words per ETS object.Sverker Eriksson
Merging the three off-heap lists (binaries, funs and externals) into one list. This reduces memory consumption by two words (pointers) per ETS object.