kernel/tools/perf/util/lock-contention.h, branch linux-6.2.y

perf lock contention: Add -L/--lock-filter option

2022-12-21T17:52:39Z

The -L/--lock-filter option is to filter only given locks. The locks can be specified by address or name (if exists). $ sudo ./perf lock record -a sleep 1 $ sudo ./perf lock con -l contended total wait max wait avg wait address symbol 57 1.11 ms 42.83 us 19.54 us ffff9f4140059000 15 280.88 us 23.51 us 18.73 us ffffffff9d007a40 jiffies_lock 1 20.49 us 20.49 us 20.49 us ffffffff9d0d50c0 rcu_state 1 9.02 us 9.02 us 9.02 us ffff9f41759e9ba0 $ sudo ./perf lock con -L jiffies_lock,rcu_state contended total wait max wait avg wait type caller 15 280.88 us 23.51 us 18.73 us spinlock tick_sched_do_timer+0x93 1 20.49 us 20.49 us 20.49 us spinlock __softirqentry_text_start+0xeb $ sudo ./perf lock con -L ffff9f4140059000 contended total wait max wait avg wait type caller 38 779.40 us 42.83 us 20.51 us spinlock worker_thread+0x50 11 216.30 us 39.87 us 19.66 us spinlock queue_work_on+0x39 8 118.13 us 20.51 us 14.77 us spinlock kthread+0xe5 Committer testing: # uname -a Linux quaco 6.0.12-200.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Dec 8 17:15:53 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux # perf lock record ^C[ perf record: Woken up 1 times to write data ] # perf lock con -L jiffies_lock,rcu_state contended total wait max wait avg wait type caller # perf lock con contended total wait max wait avg wait type caller 1 9.06 us 9.06 us 9.06 us spinlock call_timer_fn+0x24 # perf lock con -L call ignore unknown symbol: call contended total wait max wait avg wait type caller 1 9.06 us 9.06 us 9.06 us spinlock call_timer_fn+0x24 # Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Blake Jones Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221219201732.460111-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Support lock type filtering for BPF

2022-12-21T17:52:39Z

Likewise, add type_filter BPF hash map and check it when user gave a lock type filter. $ sudo ./perf lock con -ab -Y rwlock -- ./perf bench sched messaging # Running 'sched/messaging' benchmark: # 20 sender and receiver processes per group # 10 groups == 400 processes run Total time: 0.203 [sec] contended total wait max wait avg wait type caller 15 156.19 us 19.45 us 10.41 us rwlock:W do_exit+0x36d 1 11.12 us 11.12 us 11.12 us rwlock:R do_wait+0x8b 1 5.09 us 5.09 us 5.09 us rwlock:W release_task+0x6e Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Blake Jones Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221219201732.460111-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Add -Y/--type-filter option

2022-12-21T17:51:04Z

The -Y/--type-filter option is to filter the result for specific lock types only. It can accept comma-separated values. Note that it would accept type names like one in the output. spinlock, mutex, rwsem:R and so on. For RW-variant lock types, it converts the name to the both variants. In other words, "rwsem" is same as "rwsem:R,rwsem:W". Also note that "mutex" has two different encoding - one for sleeping wait, another for optimistic spinning. Add "mutex-spin" entry for the lock_type_table so that we can add it for "mutex" under the table. $ sudo ./perf lock record -a -- ./perf bench sched messaging $ sudo ./perf lock con -E 5 -Y spinlock contended total wait max wait avg wait type caller 802 1.26 ms 11.73 us 1.58 us spinlock __wake_up_common_lock+0x62 13 787.16 us 105.44 us 60.55 us spinlock remove_wait_queue+0x14 12 612.96 us 78.70 us 51.08 us spinlock prepare_to_wait+0x27 114 340.68 us 12.61 us 2.99 us spinlock try_to_wake_up+0x1f5 83 226.38 us 9.15 us 2.73 us spinlock folio_lruvec_lock_irqsave+0x5e Committer notes: Make get_type_flag() return UINT_MAX for error instad of -1UL, as that function returns 'unsigned int' and we store the value on a 'unsigned int' 'flags' variable which makes clang unhappy: 35 98.23 fedora:37 : FAIL clang version 15.0.6 (Fedora 15.0.6-1.fc37) builtin-lock.c:2012:14: error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always true [-Werror,-Wtautological-constant-out-of-range-compare] if (flags != -1UL) { ~~~~~ ^ ~~~~ builtin-lock.c:2021:14: error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always true [-Werror,-Wtautological-constant-out-of-range-compare] if (flags != -1UL) { ~~~~~ ^ ~~~~ builtin-lock.c:2037:14: error: result of comparison of constant 18446744073709551615 with expression of type 'unsigned int' is always true [-Werror,-Wtautological-constant-out-of-range-compare] if (flags != -1UL) { ~~~~~ ^ ~~~~ 3 errors generated. Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Blake Jones Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221219201732.460111-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Implement -t/--threads option for BPF

2022-12-14T14:24:31Z

The BPF didn't show the per-thread stat properly. Use task's thread id (PID) as a key instead of stack_id and add a task_data map to save task comm names. $ sudo ./perf lock con -abt -E 5 sleep 1 contended total wait max wait avg wait pid comm 1 740.66 ms 740.66 ms 740.66 ms 1950 nv_queue 3 305.50 ms 298.19 ms 101.83 ms 1884 nvidia-modeset/ 1 25.14 us 25.14 us 25.14 us 2725038 EventManager_De 12 23.09 us 9.30 us 1.92 us 0 swapper 1 20.18 us 20.18 us 20.18 us 2725033 EventManager_De Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Blake Jones Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221209190727.759804-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

machine: Adopt is_lock_function() from builtin-lock.c

2022-12-14T14:16:12Z

It is used in bpf_lock_contention.c and builtin-lock.c will be made CONFIG_LIBTRACEEVENT=y conditional, so move it to machine.c, that is always available. This makes those 4 global variables for sched and lock text start and end to move to 'struct machine' too, as conceivably we can have that info for several machine instances, say some 'perf diff' like tool. Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ian Rogers Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Stephane Eranian Cc: bpf@vger.kernel.org Link: http://lore.kernel.org/lkml/ Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Increase default stack skip to 4

2022-10-31T14:07:48Z

In most configurations, it works well with skipping 4 entries by default. If some systems still have 3 BPF internal stack frames, the next frame should be in a lock function which will be skipped later when it tries to find a caller. So increasing to 4 won't affect such systems too. With --stack-skip=0, I can see something like this: 24 49.84 us 7.41 us 2.08 us mutex bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffffc045040e bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffffc045040e bpf_prog_e1b85959d520446c_contention_begin+0x12e 0xffffffff82ea2071 bpf_trace_run2+0x51 0xffffffff82de775b __bpf_trace_contention_begin+0xb 0xffffffff82c02045 __mutex_lock+0x245 0xffffffff82c019e3 __mutex_lock_slowpath+0x13 0xffffffff82c019c0 mutex_lock+0x20 0xffffffff830a083c kernfs_iop_permission+0x2c Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221028180128.3311491-5-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Fix a build error on 32-bit

2022-10-06T11:03:51Z

It was reported that it failed to build the BPF lock contention skeleton on 32 bit arch due to the size of long. The lost count is used only for reporting errors due to lack of stackmap space through bad_hist which type is 'int'. Let's use int type then. Fixes: 6d499a6b3d90277d ("perf lock: Print the number of lost entries for BPF") Reported-by: Jiri Slaby Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Link: http://lore.kernel.org/lkml/20220926215638.3931222-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Allow to change stack depth and skip

2022-10-04T11:55:22Z

It needs stack traces to find callers of locks. To minimize the performance overhead it only collects up to 8 entries for each stack trace. And it skips first 3 entries as they came from BPF, tracepoint and lock functions which are not interested for most users. But it turned out that those numbers are different in some configuration. Using fixed number can result in non meaningful caller names. Let's make them adjustable with --stack-depth and --skip-stack options. On my setup, the default output is like below: # /perf lock con -ab -F contended,wait_total sleep 3 contended total wait type caller 28 4.55 ms rwlock:W __bpf_trace_contention_begin+0xb 33 1.67 ms rwlock:W __bpf_trace_contention_begin+0xb 12 580.28 us spinlock __bpf_trace_contention_begin+0xb 60 240.54 us rwsem:R __bpf_trace_contention_begin+0xb 27 64.45 us spinlock __bpf_trace_contention_begin+0xb If I change the stack skip to 5, the result will be like: # perf lock con -ab -F contended,wait_total --stack-skip 5 sleep 3 contended total wait type caller 32 715.45 us spinlock folio_lruvec_lock_irqsave+0x61 26 550.22 us spinlock folio_lruvec_lock_irqsave+0x61 15 486.93 us rwsem:R mmap_read_lock+0x13 12 139.66 us rwsem:W vm_mmap_pgoff+0x93 1 7.04 us spinlock tick_do_update_jiffies64+0x25 Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20220912055314.744552-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock contention: Show full callstack with -v option

2022-10-04T11:55:22Z

Currently it shows a caller function for each entry, but users need to see the full call stacks sometimes. Use -v/--verbose option to do that. # perf lock con -a -b -v sleep 3 Looking at the vmlinux_path (8 entries long) symsrc__init: cannot get elf header. Using /proc/kcore for kernel data Using /proc/kallsyms for symbols contended total wait max wait avg wait type caller 1 10.74 us 10.74 us 10.74 us spinlock __bpf_trace_contention_begin+0xb 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffbb8b8e75 bpf_trace_run2+0x35 0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb 0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5 0xffffffffbc1c26ff _raw_spin_lock+0x1f 0xffffffffbb841015 tick_do_update_jiffies64+0x25 0xffffffffbb8409ee tick_irq_enter+0x9e 1 7.70 us 7.70 us 7.70 us spinlock __bpf_trace_contention_begin+0xb 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffc03b5c47 bpf_prog_bf07ae9e2cbd02c5_contention_begin+0x117 0xffffffffbb8b8e75 bpf_trace_run2+0x35 0xffffffffbb7eab9b __bpf_trace_contention_begin+0xb 0xffffffffbb7ebe75 queued_spin_lock_slowpath+0x1f5 0xffffffffbc1c26ff _raw_spin_lock+0x1f 0xffffffffbb7bc27e raw_spin_rq_lock_nested+0xe 0xffffffffbb7cef9c load_balance+0x66c Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20220912055314.744552-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf lock: Print the number of lost entries for BPF

2022-08-02T21:03:31Z

Like the normal 'perf lock contention' output, it'd print the number of lost entries for BPF if exists or -v option is passed. Currently it uses BROKEN_CONTENDED stat for the lost count (due to full stack maps). $ sudo perf lock con -a -b --map-nr-entries 128 sleep 5 ... === output for debug=== bad: 43, total: 14903 bad rate: 0.29 % histogram of events caused bad sequence acquire: 0 acquired: 0 contended: 43 release: 0 Signed-off-by: Namhyung Kim Cc: Blake Jones Cc: Boqun Feng Cc: Davidlohr Bueso Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Song Liu Cc: Waiman Long Cc: Will Deacon Link: https://lore.kernel.org/r/20220802191004.347740-3-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo