From ede9f622af1f2634c1227a3ed5f5ea44929573d2 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Mon, 29 Dec 2014 19:41:07 +0000 Subject: [PATCH] add non-stop test that stresses thread starvation issues This commit adds a non-stop mode test originally inspired by signal-while-stepping-over-bp-other-thread.exp, that exposes the thread starvation issues fixed by the previous patches. It sets a set of threads stepping in parallel, and has one of them get a signal. Without the previous fixes, this would fail with timeouts. gdb/testsuite/ 2015-01-09 Pedro Alves * gdb.threads/non-stop-fair-events.c: New file. * gdb.threads/non-stop-fair-events.exp: New file. --- gdb/testsuite/ChangeLog | 5 + .../gdb.threads/non-stop-fair-events.c | 84 +++++++++ .../gdb.threads/non-stop-fair-events.exp | 161 ++++++++++++++++++ 3 files changed, 250 insertions(+) create mode 100644 gdb/testsuite/gdb.threads/non-stop-fair-events.c create mode 100644 gdb/testsuite/gdb.threads/non-stop-fair-events.exp diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index aa1e22b8d3e..d3dacf1ece2 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2015-01-09 Pedro Alves + + * gdb.threads/non-stop-fair-events.c: New file. + * gdb.threads/non-stop-fair-events.exp: New file. + 2015-01-09 Pedro Alves * gdb.base/annota1.exp (thread_test): Use srcfile and binfile from diff --git a/gdb/testsuite/gdb.threads/non-stop-fair-events.c b/gdb/testsuite/gdb.threads/non-stop-fair-events.c new file mode 100644 index 00000000000..6a9d31d1650 --- /dev/null +++ b/gdb/testsuite/gdb.threads/non-stop-fair-events.c @@ -0,0 +1,84 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright 2014-2015 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +#include +#include +#include +#include + +#define NUM_THREADS 10 +const int num_threads = NUM_THREADS; + +pthread_t child_thread[NUM_THREADS]; +volatile pthread_t signal_thread; +volatile int got_sig; + +void +handler (int signo) +{ + got_sig = 1; +} + +void +loop_broke (void) +{ +} + +#define INF_LOOP \ + do \ + { \ + while (!got_sig) \ + ; \ + } \ + while (0) + +void * +child_function (void *arg) +{ + pthread_t self = pthread_self (); + + while (1) + { + INF_LOOP; /* set thread breakpoint here */ + loop_broke (); + } +} + +int +main (void) +{ + int res; + int i; + + alarm (60); + + signal (SIGUSR1, handler); + + for (i = 0; i < NUM_THREADS; i++) + { + res = pthread_create (&child_thread[i], NULL, child_function, NULL); + } + + while (1) + { + pthread_kill (signal_thread, SIGUSR1); /* set kill breakpoint here */ + INF_LOOP; + loop_broke (); + } + + exit(EXIT_SUCCESS); +} diff --git a/gdb/testsuite/gdb.threads/non-stop-fair-events.exp b/gdb/testsuite/gdb.threads/non-stop-fair-events.exp new file mode 100644 index 00000000000..9b7b9ca2696 --- /dev/null +++ b/gdb/testsuite/gdb.threads/non-stop-fair-events.exp @@ -0,0 +1,161 @@ +# Copyright (C) 2014-2015 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +# Test that GDB in non-stop mode gives roughly equal priority to +# events of all threads. + +standard_testfile +set executable ${testfile} + +if [target_info exists gdb,nosignals] { + verbose "Skipping ${testfile}.exp because of nosignals." + return -1 +} + +if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] == -1} { + return -1 +} + +gdb_test_no_output "set non-stop on" + +if ![runto_main] { + return -1 +} + +# We want "handle print", to make sure the target backend reports the +# signal to the run control core. +gdb_test "handle SIGUSR1 print nostop pass" "" + +# Get current value of VAR from the inferior. TEST is used as test +# message. + +proc get_value {var test} { + global expect_out + global gdb_prompt + global decimal + + set value -1 + gdb_test_multiple "print $var" "$test" { + -re ".*= ($decimal).*\r\n$gdb_prompt $" { + set value $expect_out(1,string) + pass "$test" + } + } + return ${value} +} + +set NUM_THREADS [get_value "num_threads" "get num_threads"] + +# Account for the main thread. +incr NUM_THREADS + +# Run threads to their start positions. This prepares for a new test +# sequence. + +proc restart {} { + global gdb_prompt + global NUM_THREADS + + delete_breakpoints + + gdb_test "print got_sig = 0" " = 0" + + gdb_breakpoint [gdb_get_line_number "set thread breakpoint here"] + gdb_breakpoint [gdb_get_line_number "set kill breakpoint here"] + + set test "continue -a&" + gdb_test_multiple $test $test { + -re "Continuing.\r\n$gdb_prompt " { + pass $test + } + } + + for {set i 1} { $i <= $NUM_THREADS } { incr i } { + set test "thread $i restarted" + gdb_test_multiple "" $test { + -re "breakpoint here" { + # The prompt was already matched in the "continue &" + # test above. We're now consuming asynchronous output + # that comes after the prompt. + pass $test + } + } + } + + delete_breakpoints +} + +# The test proper. SIGNAL_THREAD is the thread that has been elected +# to receive the SIGUSR1 signal. + +proc test {signal_thread} { + global gdb_prompt + global NUM_THREADS + + with_test_prefix "signal_thread=$signal_thread" { + restart + + # Set all threads stepping the infinite loop line in parallel. + for {set i 2} { $i <= $NUM_THREADS } { incr i } { + gdb_test "thread $i" \ + "child_function.*set thread breakpoint here.*" \ + "switch to thread $i to step it" + + if {$i == $signal_thread} { + gdb_test "print signal_thread = self" " = .*" + } + + gdb_test "step&" "" "set $i thread stepping" + } + + gdb_test "thread 1" "Switching to .*" \ + "switch to the main thread to queue signal" + + # Let the main thread queue the signal. + gdb_breakpoint "loop_broke" + set test "continue &" + gdb_test_multiple $test $test { + -re "Continuing.\r\n$gdb_prompt " { + pass $test + } + } + + # Wait for all threads to finish their steps, and for the main + # thread to hit the breakpoint. + for {set i 1} { $i <= $NUM_THREADS } { incr i } { + set test "thread $i broke out of loop" + gdb_test_multiple "" $test { + -re "loop_broke" { + # The prompt was already matched in the "continue + # &" test above. We're now consuming asynchronous + # output that comes after the prompt. + pass $test + } + } + } + + # It's helpful to have this in the log if the test ever + # happens to fail. + gdb_test "info threads" + } +} + +# The kernel/debug API may always walk its thread list looking for the +# first with an event, resulting in giving priority to e.g. the thread +# with lowest kernel thread ID. So test once with the signal pending +# in each thread, except the main thread. +for {set i 2} { $i <= $NUM_THREADS } { incr i } { + test $i +} -- 2.30.2