From 1580937874b35350c0ff5c2a72b2540d7ec28378 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Tue, 15 Feb 2011 14:48:08 +0100 Subject: Allow unexpected driver input event in driver_SUITE:smp_select epoll on Linux has been seen to sometimes trigger unexpected events. Most of the time these events are filtered by erl_check_io, but may slip up to the driver in cases when fd's are reused. Also made clear in driver docs that spurious events may happen. --- erts/doc/src/driver_entry.xml | 6 +++++- erts/emulator/test/driver_SUITE.erl | 4 ++-- erts/emulator/test/driver_SUITE_data/chkio_drv.c | 15 ++++++++++++--- 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/erts/doc/src/driver_entry.xml b/erts/doc/src/driver_entry.xml index dd949d4048..7d1585f483 100644 --- a/erts/doc/src/driver_entry.xml +++ b/erts/doc/src/driver_entry.xml @@ -4,7 +4,7 @@
- 20012010 + 20012011 Ericsson AB. All Rights Reserved. @@ -219,6 +219,10 @@ typedef struct erl_drv_entry { completes, write to the pipe (use SetEvent on Windows), this will make the emulator call ready_input or ready_output.

+

Spurious events may happen. That is, calls to ready_input + or ready_output even though no real events are signaled. In + reality it should be rare (and OS dependant), but a robust driver + must nevertheless be able to handle such cases.

char *driver_name diff --git a/erts/emulator/test/driver_SUITE.erl b/erts/emulator/test/driver_SUITE.erl index 39b2ed395f..e029e4ec87 100644 --- a/erts/emulator/test/driver_SUITE.erl +++ b/erts/emulator/test/driver_SUITE.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1997-2009. All Rights Reserved. +%% Copyright Ericsson AB 1997-2011. All Rights Reserved. %% %% The contents of this file are subject to the Erlang Public License, %% Version 1.1, (the "License"); you may not use this file except in @@ -1682,7 +1682,7 @@ smp_select0(Config) -> ProcFun = fun()-> io:format("Worker ~p starting\n",[self()]), ?line Port = open_port({spawn, DrvName}, []), smp_select_loop(Port, 100000), - sleep(500), % wait for driver to handle pending events + sleep(1000), % wait for driver to handle pending events ?line true = erlang:port_close(Port), Master ! {ok,self()}, io:format("Worker ~p finished\n",[self()]) diff --git a/erts/emulator/test/driver_SUITE_data/chkio_drv.c b/erts/emulator/test/driver_SUITE_data/chkio_drv.c index b571cb30e6..bbdb09cfcb 100644 --- a/erts/emulator/test/driver_SUITE_data/chkio_drv.c +++ b/erts/emulator/test/driver_SUITE_data/chkio_drv.c @@ -102,6 +102,7 @@ typedef struct chkio_smp_select { int write_fd; int next_read; int next_write; + int first_write; enum {Closed, Opened, Selected, Waiting} state; int wasSelected; unsigned rand_state; @@ -577,9 +578,16 @@ chkio_drv_ready_input(ErlDrvData drv_data, ErlDrvEvent event) inPipe = (pip->next_write - pip->next_read); if (inPipe == 0) { bytes = read(pip->read_fd, &word, sizeof(word)); - printf("Unexpected empty pipe, expected %u -> %u, bytes=%d, word=%d\n", - pip->next_read, pip->next_write-1, bytes, word); - abort(); + printf("Unexpected empty pipe, expected %u -> %u, bytes=%d, word=%d, written=%d\n", + pip->next_read, pip->next_write-1, bytes, word, + (pip->next_write - pip->first_write)); + /*abort(); + Allow unexpected events as it's been seen to be triggered by epoll + on Linux. Most of the time the unwanted events are filtered by + the erl_check_io layer. But when fd's are reused the events may + slip up to the driver. + */ + break; } n = rand_r(&pip->rand_state) % (inPipe*4); @@ -1252,6 +1260,7 @@ chkio_drv_control(ErlDrvData drv_data, pip->state = Opened; pip->wasSelected = 0; pip->next_write = pip->next_read = rand_r(&pip->rand_state) % 1024; + pip->first_write = pip->next_write; if (op & 1) break; op >>= 1; }/*fall through*/ -- cgit v1.2.3