Remove all mention of efile_drv from DTrace docs

efile_drv is gone and so is the need for file-specific DTrace. The
new implementation works fine with the normal tracing mechanism so
there's nothing preventing anyone from making an erl_tracer nif
that forward these events to DTrace.

1 files changed, 4 insertions, 339 deletions

diff --git a/HOWTO/DTRACE.md b/HOWTO/DTRACE.md
index 90f4addefd..0c08b6cc3d 100644
--- a/HOWTO/DTRACE.md
+++ b/HOWTO/DTRACE.md
@@ -46,346 +46,11 @@ although it's considered experimental. The main development of the dtrace code
 still happens outside of Ericsson, but there is no need to fetch a patched 
 version of the OTP source to get the basic funtionality.
 
-Implementation summary
-----------------------
+DTrace probe specifications
+---------------------------
 
-So far, most effort has been focused on the `efile_drv.c` code,
-which implements most file I/O on behalf of the Erlang virtual
-machine.  This driver also presents a big challenge: its use of an I/O
-worker pool (enabled by using the `erl +A 8` flag, for example) makes
-it much more difficult to trace I/O activity because each of the
-following may be executed in a different Pthread:
-
-* I/O initiation (Erlang code)
-* I/O proxy process handling, e.g. read/write when file is not opened
-  in `raw` mode, operations executed by the code & file server processes.
-  (Erlang code)
-* `efile_drv` command setup (C code)
-* `efile_drv` command execution (C code)
-* `efile_drv` status return (C code)
-
-Example output from `lib/runtime_tools/examples/efile_drv.d` while executing
-`file:rename("old-name", "new-name")`:
-
-    efile_drv enter tag={3,84} user tag some-user-tag | RENAME (12) | args: old-name new-name ,\
-          0 0 (port #Port<0.59>)
-    async I/O worker tag={3,83} | RENAME (12) | efile_drv-int_entry
-    async I/O worker tag={3,83} | RENAME (12) | efile_drv-int_return
-    efile_drv return tag={3,83} user tag  | RENAME (12) | errno 2
-
-... where the following key can help decipher the output:
-
-* `{3,83}` is the Erlang scheduler thread number (3) and operation
-  counter number (83) assigned to this I/O operation.  Together,
-  these two numbers form a unique ID for the I/O operation.
-* `12` is the command number for the rename operation.  See the
-  definition for `FILE_RENAME` in the source code file `efile_drv.c`
-  or the `BEGIN` section of the D script `lib/runtime_tools/examples/efile_drv.d`.
-* `old-name` and `new-name` are the two string arguments for the
-  source and destination of the `rename(2)` system call.
-  The two integer arguments are unused; the simple formatting code
-  prints the arguments anyway, 0 and 0.
-* The worker pool code was called on behalf of Erlang port `#Port<0.59>`.
-* The system call failed with a POSIX errno value of 2: `ENOENT`,
-  because the path `old-name` does not exist.
-* The `efile_drv-int_entry` and `efile_drv_int_return` probes are
-  provided in case the user is
-  interested in measuring only the latency of code executed by
-  `efile_drv` asynchronous functions by I/O worker pool threads
-  and the OS system call that they encapsulate.
-
-So, where does the `some-user-tag` string come from?
-
-At the moment, the user tag comes from code like the following:
-
-    dyntrace:put_tag("some-user-tag"),
-    file:rename("old-name", "new-name"),
-
-This method of tagging I/O at the Erlang level is subject to change.
-
-Example DTrace probe specification
-----------------------------------
-
-    /**
-     * Fired when a message is sent from one local process to another.
-     *
-     * NOTE: The 'size' parameter is in machine-dependent words and
-     *       that the actual size of any binary terms in the message
-     *       are not included.
-     *
-     * @param sender the PID (string form) of the sender
-     * @param receiver the PID (string form) of the receiver
-     * @param size the size of the message being delivered (words)
-     * @param token_label for the sender's sequential trace token
-     * @param token_previous count for the sender's sequential trace token
-     * @param token_current count for the sender's sequential trace token
-     */
-    probe message__send(char *sender, char *receiver, uint32_t size,
-                        int token_label, int token_previous, int token_current);
-
-    /**
-     * Fired when a message is sent from a local process to a remote process.
-     *
-     * NOTE: The 'size' parameter is in machine-dependent words and
-     *       that the actual size of any binary terms in the message
-     *       are not included.
-     *
-     * @param sender the PID (string form) of the sender
-     * @param node_name the Erlang node name (string form) of the receiver
-     * @param receiver the PID/name (string form) of the receiver
-     * @param size the size of the message being delivered (words)
-     * @param token_label for the sender's sequential trace token
-     * @param token_previous count for the sender's sequential trace token
-     * @param token_current count for the sender's sequential trace token
-     */
-    probe message__send__remote(char *sender, char *node_name, char *receiver,
-                                uint32_t size,
-                        int token_label, int token_previous, int token_current);
-
-    /**
-     * Fired when a message is queued to a local process.  This probe
-     * will not fire if the sender's pid == receiver's pid.
-     *
-     * NOTE: The 'size' parameter is in machine-dependent words and
-     *       that the actual size of any binary terms in the message
-     *       are not included.
-     *
-     * @param receiver the PID (string form) of the receiver
-     * @param size the size of the message being delivered (words)
-     * @param queue_len length of the queue of the receiving process
-     * @param token_label for the sender's sequential trace token
-     * @param token_previous count for the sender's sequential trace token
-     * @param token_current count for the sender's sequential trace token
-     */
-    probe message__queued(char *receiver, uint32_t size, uint32_t queue_len,
-                        int token_label, int token_previous, int token_current);
-
-    /**
-     * Fired when a message is 'receive'd by a local process and removed
-     * from its mailbox.
-     *
-     * NOTE: The 'size' parameter is in machine-dependent words and
-     *       that the actual size of any binary terms in the message
-     *       are not included.
-     *
-     * @param receiver the PID (string form) of the receiver
-     * @param size the size of the message being delivered (words)
-     * @param queue_len length of the queue of the receiving process
-     * @param token_label for the sender's sequential trace token
-     * @param token_previous count for the sender's sequential trace token
-     * @param token_current count for the sender's sequential trace token
-     */
-    probe message__receive(char *receiver, uint32_t size, uint32_t queue_len,
-                        int token_label, int token_previous, int token_current);
-
-    /* ... */
-
-    /* Async driver pool */
-
-    /**
-     * Show the post-add length of the async driver thread pool member's queue.
-     *
-     * NOTE: The port name is not available: additional lock(s) must
-     *       be acquired in order to get the port name safely in an SMP
-     *       environment.  The same is true for the aio__pool_get probe.
-     *
-     * @param port the Port (string form)
-     * @param new queue length
-     */
-    probe aio_pool__add(char *, int);
-
-    /**
-     * Show the post-get length of the async driver thread pool member's queue.
-     *
-     * @param port the Port (string form)
-     * @param new queue length
-     */
-    probe aio_pool__get(char *, int);
-
-    /* Probes for efile_drv.c */
-
-    /**
-     * Entry into the efile_drv.c file I/O driver
-     *
-     * For a list of command numbers used by this driver, see the section
-     * "Guide to probe arguments" in ../../../README.md.  That section
-     * also contains explanation of the various integer and string
-     * arguments that may be present when any particular probe fires.
-     *
-     * TODO: Adding the port string, args[10], is a pain.  Making that
-     *       port string available to all the other efile_drv.c probes
-     *       will be more pain.  Is the pain worth it?  If yes, then
-     *       add them everywhere else and grit our teeth.  If no, then
-     *       rip it out.
-     *
-     * @param thread-id number of the scheduler Pthread                   arg0
-     * @param tag number: {thread-id, tag} uniquely names a driver operation
-     * @param user-tag string                                             arg2
-     * @param command number                                              arg3
-     * @param string argument 1                                           arg4
-     * @param string argument 2                                           arg5
-     * @param integer argument 1                                          arg6
-     * @param integer argument 2                                          arg7
-     * @param integer argument 3                                          arg8
-     * @param integer argument 4                                          arg9
-     * @param port the port ID of the busy port                       args[10]
-     */
-    probe efile_drv__entry(int, int, char *, int, char *, char *,
-                           int64_t, int64_t, int64_t, int64_t, char *);
-
-    /**
-     * Entry into the driver's internal work function.  Computation here
-     * is performed by a async worker pool Pthread.
-     *
-     * @param thread-id number
-     * @param tag number
-     * @param command number
-     */
-    probe efile_drv__int_entry(int, int, int);
-
-    /**
-     * Return from the driver's internal work function.
-     *
-     * @param thread-id number
-     * @param tag number
-     * @param command number
-     */
-    probe efile_drv__int_return(int, int, int);
-
-    /**
-     * Return from the efile_drv.c file I/O driver
-     *
-     * @param thread-id number                                            arg0
-     * @param tag number                                                  arg1
-     * @param user-tag string                                             arg2
-     * @param command number                                              arg3
-     * @param Success? 1 is success, 0 is failure                         arg4
-     * @param If failure, the errno of the error.                         arg5
-     */
-    probe efile_drv__return(int, int, char *, int, int, int);
-
-Guide to efile_drv.c probe arguments
-------------------------------------
-
-    /* Driver op code: used by efile_drv-entry      arg3 */
-    /*                 used by efile_drv-int_entry  arg3 */
-    /*                 used by efile_drv-int_return arg3 */
-    /*                 used by efile_drv-return     arg3 */
-
-    #define FILE_OPEN            1                 (probe arg3)
-            probe arg6 = C driver dt_i1 = flags;
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_READ            2                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = size;
-
-    #define FILE_LSEEK           3                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = offset;
-            probe arg8 = C driver dt_i3 = origin;
-
-    #define FILE_WRITE           4                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = size;
-
-    #define FILE_FSTAT           5                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-
-    #define FILE_PWD             6                 (probe arg3)
-            none
-
-    #define FILE_READDIR         7                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_CHDIR           8                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_FSYNC           9                 (probe arg3)
-                probe arg6 = C driver dt_i1 = fd;
-
-    #define FILE_MKDIR          10                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_DELETE         11                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_RENAME         12                 (probe arg3)
-            probe arg4 = C driver dt_s1 = old_name;
-            probe arg5 = C driver dt_s2 = new_name;
-
-    #define FILE_RMDIR          13                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_TRUNCATE       14                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-
-    #define FILE_READ_FILE      15                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_WRITE_INFO     16                 (probe arg3)
-            probe arg6 = C driver dt_i1 = mode;
-            probe arg7 = C driver dt_i2 = uid;
-            probe arg8 = C driver dt_i3 = gid;
-
-    #define FILE_LSTAT          19                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_READLINK       20                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_LINK           21                 (probe arg3)
-            probe arg4 = C driver dt_s1 = existing_path;
-            probe arg5 = C driver dt_s2 = new_path;
-
-    #define FILE_SYMLINK        22                 (probe arg3)
-            probe arg4 = C driver dt_s1 = existing_path;
-            probe arg5 = C driver dt_s2 = new_path;
-
-    #define FILE_CLOSE          23                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-
-    #define FILE_PWRITEV        24                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = size;
-
-    #define FILE_PREADV         25                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = size;
-
-    #define FILE_SETOPT         26                 (probe arg3)
-            probe arg6 = C driver dt_i1 = opt_name;
-            probe arg7 = C driver dt_i2 = opt_specific_value;
-
-    #define FILE_IPREAD         27                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = offsets[0];
-            probe arg9 = C driver dt_i4 = size;
-
-    #define FILE_ALTNAME        28                 (probe arg3)
-            probe arg4 = C driver dt_s1 = path;
-
-    #define FILE_READ_LINE      29                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = flags;
-            probe arg8 = C driver dt_i3 = read_offset;
-            probe arg9 = C driver dt_i4 = read_ahead;
-
-    #define FILE_FDATASYNC      30                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-
-    #define FILE_FADVISE        31                 (probe arg3)
-            probe arg6 = C driver dt_i1 = fd;
-            probe arg7 = C driver dt_i2 = offset;
-            probe arg8 = C driver dt_i3 = length;
-            probe arg9 = C driver dt_i4 = advise_type;
+Probe specifications can be found in `erts/emulator/beam/erlang_dtrace.d`, and
+a few example scripts can be found under `lib/runtime_tools/examples/`.
 
    [1]: http://www.erlang.org/euc/08/
    [$ERL_TOP/HOWTO/SYSTEMTAP.md]: SYSTEMTAP.md