changes in v4:
- Add enum support to tracepoint arguments
- For tracing syscalls, move trace__load_vmlinux_btf() to
syscall__set_arg_fmts() to make it more elegant
changes in v3:
- Fixed another awkward formatting issue in trace__load_vmlinux_btf()
changes in v2:
- Fix formatting issues
- Pass a &use_btf to syscall_arg_fmt__init_array(), instead of
traversing all the arguments again.
- Add a trace__load_vmlinux_btf() function to load vmlinux BTF
- Add member 'btf_entry' in 'struct syscall_arg_fmt' to save the entry to
the corresponding 'struct btf_member' object, without having to do
btf__find_by_name(), btf__type_by_id(), btf_enum(), and btf_vlen()
everytime a syscall enters.
===
v4 notes
before:
perf $ ./perf trace -e timer:hrtimer_start --max-events=1
0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466c25f18, function: 0xffffffff89da5be0, expires: 377432432256753, softexpires: 377432432256753, mode: 10)
after:
perf $ ./perf trace -e timer:hrtimer_start --max-events=1
0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466c25f18, function: 0xffffffff89da5be0, expires: 377732805560049, softexpires: 377732805560049, mode: HRTIMER_MODE_ABS_PINNED_HARD)
HRTIMER_MODE_ABS_PINNED_HARD is:
perf $ pahole hrtimer_mode
enum hrtimer_mode {
HRTIMER_MODE_ABS = 0,
HRTIMER_MODE_REL = 1,
HRTIMER_MODE_PINNED = 2,
HRTIMER_MODE_SOFT = 4,
HRTIMER_MODE_HARD = 8,
HRTIMER_MODE_ABS_PINNED = 2,
HRTIMER_MODE_REL_PINNED = 3,
HRTIMER_MODE_ABS_SOFT = 4,
HRTIMER_MODE_REL_SOFT = 5,
HRTIMER_MODE_ABS_PINNED_SOFT = 6,
HRTIMER_MODE_REL_PINNED_SOFT = 7,
HRTIMER_MODE_ABS_HARD = 8,
HRTIMER_MODE_REL_HARD = 9,
HRTIMER_MODE_ABS_PINNED_HARD = 10,
HRTIMER_MODE_REL_PINNED_HARD = 11,
};
this: HRTIMER_MODE_ABS_PINNED_HARD = 10,
Can also be tested by
./perf trace -e pagemap:mm_lru_insertion,timer:hrtimer_start,timer:hrtimer_init,skb:kfree_skb --max-events=10
(Chose these 4 tracepoints because they happen quite frequently.)
By using the command above, I got:
perf $ ./perf trace -e pagemap:mm_lru_insertion,timer:hrtimer_start,timer:hrtimer_init,skb:kfree_skb --max-events=10
0.000 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466c25f18, function: 0xffffffff89da5be0, expires: 376189979047665, softexpires: 376189979047665, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.053 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376230939043569, softexpires: 376230939043569, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.099 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376111885722141, softexpires: 376111885722141, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.242 tmux: server/296019 timer:hrtimer_init(hrtimer: 0xffffb872caa1f628, clockid: 1, mode: HRTIMER_MODE_ABS)
0.244 tmux: server/296019 timer:hrtimer_start(hrtimer: 0xffffb872caa1f628, function: 0xffffffff89d90420, expires: 376111894496606, softexpires: 376111894446606, mode: HRTIMER_MODE_ABS)
0.349 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376230939043569, softexpires: 376230939043569, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.486 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376111885722141, softexpires: 376111885722141, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.499 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376230939043569, softexpires: 376230939043569, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.501 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376111885722141, softexpires: 376111885722141, mode: HRTIMER_MODE_ABS_PINNED_HARD)
0.506 :0/0 timer:hrtimer_start(hrtimer: 0xffff974466ca5f18, function: 0xffffffff89da5be0, expires: 376230939043569, softexpires: 376230939043569, mode: HRTIMER_MODE_ABS_PINNED_HARD)
If you want to test all tracepoints that has enum arguments, and
that enum argument is retrievable in vmlinux:
./perf trace -e power:dev_pm_qos_add_request,power:dev_pm_qos_remove_request,power:dev_pm_qos_update_request,error_report:error_report_end,error_report:error_report_end,timer:hrtimer_init,timer:hrtimer_start,i2c_slave:i2c_slave,cfg80211:cfg80211_get_bss,pagemap:mm_lru_insertion,migrate:mm_migrate_pages,migrate:mm_migrate_pages_start,cfg80211:rdev_auth,cfg80211:rdev_connect,cfg80211:rdev_start_ap,cfg80211:cfg80211_chandef_dfs_required,cfg80211:cfg80211_ch_switch_notify,cfg80211:cfg80211_ch_switch_started_notify,cfg80211:cfg80211_get_bss,cfg80211:cfg80211_ibss_joined,cfg80211:cfg80211_inform_bss_frame,cfg80211:cfg80211_radar_event,cfg80211:cfg80211_ready_on_channel_expired,cfg80211:cfg80211_ready_on_channel,cfg80211:cfg80211_reg_can_beacon,cfg80211:cfg80211_return_bss,cfg80211:cfg80211_tx_mgmt_expired,cfg80211:rdev_channel_switch,cfg80211:rdev_inform_bss,cfg80211:rdev_libertas_set_mesh_channel,cfg80211:rdev_mgmt_tx,cfg80211:rdev_remain_on_channel,cfg80211:rdev_return_chandef,cfg80211:rdev_return_int_survey_info,cfg80211:rdev_set_ap_chanwidth,cfg80211:rdev_set_monitor_channel,cfg80211:rdev_set_radar_background,cfg80211:rdev_start_ap,cfg80211:rdev_start_radar_detection,cfg80211:rdev_tdls_channel_switch,cfg80211:cfg80211_reg_can_beacon,cfg80211:rdev_add_virtual_intf,cfg80211:rdev_change_virtual_intf,sched:sched_skip_vma_numa,power:pm_qos_update_flags,power:pm_qos_update_target,pwm:pwm_apply,pwm:pwm_get,skb:kfree_skb,thermal:thermal_zone_trip,xen:xen_mc_batch,xen:xen_mc_issue,xen:xen_mc_extend_args,xen:xen_mc_extend_args,xen:xen_mc_flush_reason,xen:xen_mc_flush_reason,compaction:mm_compaction_defer_compaction,compaction:mm_compaction_deferred,compaction:mm_compaction_defer_reset,compaction:mm_compaction_finished,compaction:mm_compaction_kcompactd_wake,compaction:mm_compaction_suitable,compaction:mm_compaction_wakeup_kcompactd --max-events=20
But whether this enum is in vmlinux may vary on different versions.
If you want to find out which enum type is in vmlinux, please use:
vmlinux_dir $ bpftool btf dump file /sys/kernel/btf/vmlinux > vmlinux
vmlinux_dir $ while read l; do grep "ENUM '$l'" vmlinux; done < <(grep field:enum /sys/kernel/tracing/events/*/*/format | awk '{print $3}' | sort | uniq) | awk '{print $3}' | sed "s/'\(.*\)'/\1/g"
dev_pm_qos_req_type
error_detector
hrtimer_mode
i2c_slave_event
ieee80211_bss_type
lru_list
migrate_mode
nl80211_auth_type
nl80211_band
nl80211_iftype
numa_vmaskip_reason
pm_qos_req_action
pwm_polarity
skb_drop_reason
thermal_trip_type
xen_lazy_mode
xen_mc_extend_args
xen_mc_flush_reason
zone_type
And what tracepoints have these enum types as their arguments:
vmlinux_dir $ while read l; do grep "ENUM '$l'" vmlinux; done < <(grep field:enum /sys/kernel/tracing/events/*/*/format | awk '{print $3}' | sort | uniq) | awk '{print $3}' | sed "s/'\(.*\)'/\1/g" > good_enums
vmlinux_dir $ cat good_enums
dev_pm_qos_req_type
error_detector
hrtimer_mode
i2c_slave_event
ieee80211_bss_type
lru_list
migrate_mode
nl80211_auth_type
nl80211_band
nl80211_iftype
numa_vmaskip_reason
pm_qos_req_action
pwm_polarity
skb_drop_reason
thermal_trip_type
xen_lazy_mode
xen_mc_extend_args
xen_mc_flush_reason
zone_type
vmlinux_dir $ grep -f good_enums -l /sys/kernel/tracing/events/*/*/format
/sys/kernel/tracing/events/cfg80211/cfg80211_chandef_dfs_required/format
/sys/kernel/tracing/events/cfg80211/cfg80211_ch_switch_notify/format
/sys/kernel/tracing/events/cfg80211/cfg80211_ch_switch_started_notify/format
/sys/kernel/tracing/events/cfg80211/cfg80211_get_bss/format
/sys/kernel/tracing/events/cfg80211/cfg80211_ibss_joined/format
/sys/kernel/tracing/events/cfg80211/cfg80211_inform_bss_frame/format
/sys/kernel/tracing/events/cfg80211/cfg80211_radar_event/format
/sys/kernel/tracing/events/cfg80211/cfg80211_ready_on_channel_expired/format
/sys/kernel/tracing/events/cfg80211/cfg80211_ready_on_channel/format
/sys/kernel/tracing/events/cfg80211/cfg80211_reg_can_beacon/format
/sys/kernel/tracing/events/cfg80211/cfg80211_return_bss/format
/sys/kernel/tracing/events/cfg80211/cfg80211_tx_mgmt_expired/format
/sys/kernel/tracing/events/cfg80211/rdev_add_virtual_intf/format
/sys/kernel/tracing/events/cfg80211/rdev_auth/format
/sys/kernel/tracing/events/cfg80211/rdev_change_virtual_intf/format
/sys/kernel/tracing/events/cfg80211/rdev_channel_switch/format
/sys/kernel/tracing/events/cfg80211/rdev_connect/format
/sys/kernel/tracing/events/cfg80211/rdev_inform_bss/format
/sys/kernel/tracing/events/cfg80211/rdev_libertas_set_mesh_channel/format
/sys/kernel/tracing/events/cfg80211/rdev_mgmt_tx/format
/sys/kernel/tracing/events/cfg80211/rdev_remain_on_channel/format
/sys/kernel/tracing/events/cfg80211/rdev_return_chandef/format
/sys/kernel/tracing/events/cfg80211/rdev_return_int_survey_info/format
/sys/kernel/tracing/events/cfg80211/rdev_set_ap_chanwidth/format
/sys/kernel/tracing/events/cfg80211/rdev_set_monitor_channel/format
/sys/kernel/tracing/events/cfg80211/rdev_set_radar_background/format
/sys/kernel/tracing/events/cfg80211/rdev_start_ap/format
/sys/kernel/tracing/events/cfg80211/rdev_start_radar_detection/format
/sys/kernel/tracing/events/cfg80211/rdev_tdls_channel_switch/format
/sys/kernel/tracing/events/compaction/mm_compaction_defer_compaction/format
/sys/kernel/tracing/events/compaction/mm_compaction_deferred/format
/sys/kernel/tracing/events/compaction/mm_compaction_defer_reset/format
/sys/kernel/tracing/events/compaction/mm_compaction_finished/format
/sys/kernel/tracing/events/compaction/mm_compaction_kcompactd_wake/format
/sys/kernel/tracing/events/compaction/mm_compaction_suitable/format
/sys/kernel/tracing/events/compaction/mm_compaction_wakeup_kcompactd/format
/sys/kernel/tracing/events/error_report/error_report_end/format
/sys/kernel/tracing/events/i2c_slave/i2c_slave/format
/sys/kernel/tracing/events/migrate/mm_migrate_pages/format
/sys/kernel/tracing/events/migrate/mm_migrate_pages_start/format
/sys/kernel/tracing/events/pagemap/mm_lru_insertion/format
/sys/kernel/tracing/events/power/dev_pm_qos_add_request/format
/sys/kernel/tracing/events/power/dev_pm_qos_remove_request/format
/sys/kernel/tracing/events/power/dev_pm_qos_update_request/format
/sys/kernel/tracing/events/power/pm_qos_update_flags/format
/sys/kernel/tracing/events/power/pm_qos_update_target/format
/sys/kernel/tracing/events/pwm/pwm_apply/format
/sys/kernel/tracing/events/pwm/pwm_get/format
/sys/kernel/tracing/events/sched/sched_skip_vma_numa/format
/sys/kernel/tracing/events/skb/kfree_skb/format
/sys/kernel/tracing/events/thermal/thermal_zone_trip/format
/sys/kernel/tracing/events/timer/hrtimer_init/format
/sys/kernel/tracing/events/timer/hrtimer_start/format
/sys/kernel/tracing/events/xen/xen_mc_batch/format
/sys/kernel/tracing/events/xen/xen_mc_extend_args/format
/sys/kernel/tracing/events/xen/xen_mc_flush_reason/format
/sys/kernel/tracing/events/xen/xen_mc_issue/format
This is how I got the crazy long list of tracepoints above.
