diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2023-05-01 13:34:43 -0400 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2023-05-10 14:16:54 +0200 |
| commit | 58a2e3f5c37be02dac3086b81bdda9414b931edf (patch) | |
| tree | c7d848ec1ee79f0b784decade1800867e67f0315 | |
| parent | e19b157f3c66c44e3b89cb50a2030f0187b968e9 (diff) | |
block: compile out assert_bdrv_graph_readable() by default
reader_count() is a performance bottleneck because the global
aio_context_list_lock mutex causes thread contention. Put this debugging
assertion behind a new ./configure --enable-debug-graph-lock option and
disable it by default.
The --enable-debug-graph-lock option is also enabled by the more general
--enable-debug option.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230501173443.153062-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/graph-lock.c | 3 | ||||
| -rwxr-xr-x | configure | 1 | ||||
| -rw-r--r-- | meson.build | 2 | ||||
| -rw-r--r-- | meson_options.txt | 2 | ||||
| -rw-r--r-- | scripts/meson-buildoptions.sh | 4 |
5 files changed, 12 insertions, 0 deletions
diff --git a/block/graph-lock.c b/block/graph-lock.c index 639526608f..377884c3a9 100644 --- a/block/graph-lock.c +++ b/block/graph-lock.c @@ -265,7 +265,10 @@ void bdrv_graph_rdunlock_main_loop(void) void assert_bdrv_graph_readable(void) { + /* reader_count() is slow due to aio_context_list_lock lock contention */ +#ifdef CONFIG_DEBUG_GRAPH_LOCK assert(qemu_in_main_thread() || reader_count()); +#endif } void assert_bdrv_graph_writable(void) @@ -816,6 +816,7 @@ for opt do --enable-debug) # Enable debugging options that aren't excessively noisy debug_tcg="yes" + meson_option_parse --enable-debug-graph-lock "" meson_option_parse --enable-debug-mutex "" meson_option_add -Doptimization=0 fortify_source="no" diff --git a/meson.build b/meson.build index c56e0fec9e..646555420f 100644 --- a/meson.build +++ b/meson.build @@ -1963,6 +1963,7 @@ if get_option('debug_stack_usage') and have_coroutine_pool have_coroutine_pool = false endif config_host_data.set10('CONFIG_COROUTINE_POOL', have_coroutine_pool) +config_host_data.set('CONFIG_DEBUG_GRAPH_LOCK', get_option('debug_graph_lock')) config_host_data.set('CONFIG_DEBUG_MUTEX', get_option('debug_mutex')) config_host_data.set('CONFIG_DEBUG_STACK_USAGE', get_option('debug_stack_usage')) config_host_data.set('CONFIG_GPROF', get_option('gprof')) @@ -3841,6 +3842,7 @@ summary_info += {'PIE': get_option('b_pie')} summary_info += {'static build': config_host.has_key('CONFIG_STATIC')} summary_info += {'malloc trim support': has_malloc_trim} summary_info += {'membarrier': have_membarrier} +summary_info += {'debug graph lock': get_option('debug_graph_lock')} summary_info += {'debug stack usage': get_option('debug_stack_usage')} summary_info += {'mutex debugging': get_option('debug_mutex')} summary_info += {'memory allocator': get_option('malloc')} diff --git a/meson_options.txt b/meson_options.txt index 66ca350029..d8330a1f71 100644 --- a/meson_options.txt +++ b/meson_options.txt @@ -319,6 +319,8 @@ option('rng_none', type: 'boolean', value: false, description: 'dummy RNG, avoid using /dev/(u)random and getrandom()') option('coroutine_pool', type: 'boolean', value: true, description: 'coroutine freelist (better performance)') +option('debug_graph_lock', type: 'boolean', value: false, + description: 'graph lock debugging support') option('debug_mutex', type: 'boolean', value: false, description: 'mutex debugging support') option('debug_stack_usage', type: 'boolean', value: false, diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh index 34d82dec53..2805d1c145 100644 --- a/scripts/meson-buildoptions.sh +++ b/scripts/meson-buildoptions.sh @@ -23,6 +23,8 @@ meson_options_help() { printf "%s\n" ' QEMU' printf "%s\n" ' --enable-cfi Control-Flow Integrity (CFI)' printf "%s\n" ' --enable-cfi-debug Verbose errors in case of CFI violation' + printf "%s\n" ' --enable-debug-graph-lock' + printf "%s\n" ' graph lock debugging support' printf "%s\n" ' --enable-debug-mutex mutex debugging support' printf "%s\n" ' --enable-debug-stack-usage' printf "%s\n" ' measure coroutine stack usage' @@ -254,6 +256,8 @@ _meson_option_parse() { --datadir=*) quote_sh "-Ddatadir=$2" ;; --enable-dbus-display) printf "%s" -Ddbus_display=enabled ;; --disable-dbus-display) printf "%s" -Ddbus_display=disabled ;; + --enable-debug-graph-lock) printf "%s" -Ddebug_graph_lock=true ;; + --disable-debug-graph-lock) printf "%s" -Ddebug_graph_lock=false ;; --enable-debug-mutex) printf "%s" -Ddebug_mutex=true ;; --disable-debug-mutex) printf "%s" -Ddebug_mutex=false ;; --enable-debug-stack-usage) printf "%s" -Ddebug_stack_usage=true ;; |