[PATCH v2] perf_event_open.2: Update man page with recent changes
From: Alejandro Colomar
Date: Thu Nov 05 2020 - 10:31:28 EST
From: Namhyung Kim <namhyung@xxxxxxxxx>
There are lots of changes as usual. I've tried to fill some missing
bits in the man page but it'd be nice if you could take a look and put
more info there.
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
[colomar.6.4.3@xxxxxxxxx: ffix + tfix]
Co-developed-by : Alejandro Colomar <colomar.6.4.3@xxxxxxxxx>
Signed-off-by: Alejandro Colomar <colomar.6.4.3@xxxxxxxxx>
---
I wrapped a few lines, and did some formatting fixes to the patch.
However, there are some parts where
I found the text to be a bit unclear to me.
Maybe you could rephrase them:
- The paragraph right under 'write_backward'.
- Text right under 'text_poke': "there's a changes"
I would cheange
[[
struct { u64 dev, inode } [nr_namespaces];
]]
to
[[
struct {
u64 dev;
u64 inode;
} [nr_namespaces];
]]
Woudln't you?
Thanks,
Alex
man2/perf_event_open.2 | 265 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 263 insertions(+), 2 deletions(-)
diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index 72afafb50..4adeccdde 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -247,8 +247,17 @@ struct perf_event_attr {
due to exec */
use_clockid : 1, /* use clockid for time fields */
context_switch : 1, /* context switch data */
+ write_backward : 1, /* Write ring buffer from end
+ to beginning */
+ namespaces : 1, /* include namespaces data */
+ ksymbol : 1, /* include ksymbol events */
+ bpf_event : 1, /* include bpf events */
+ aux_output : 1, /* generate AUX records
+ instead of events */
+ cgroup : 1, /* include cgroup events */
+ text_poke : 1, /* include text poke events */
- __reserved_1 : 37;
+ __reserved_1 : 30;
union {
__u32 wakeup_events; /* wakeup every n events */
@@ -854,6 +863,20 @@ is set higher than zero then the register
values returned are those captured by
hardware at the time of the sampled
instruction's retirement.
+.TP
+.BR PERF_SAMPLE_PHYS_ADDR " (since Linux 4.13)"
+.\" commit fc7ce9c74c3ad232b084d80148654f926d01ece7
+Records physical address of data like in
+.B PERF_SAMPLE_ADDR .
+.TP
+.BR PERF_SAMPLE_CGROUP " (since Linux 5.7)"
+.\" commit 96aaab686505c449e24d76e76507290dcc30e008
+Records (perf_event) cgroup id of the process.
+This corresponds to the
+.I id
+field in the
+.B PERF_RECORD_CGROUP
+event.
.RE
.TP
.IR "read_format"
@@ -1189,6 +1212,47 @@ information even with strict
.I perf_event_paranoid
settings.
.TP
+.IR write_backward " (since Linux 4.6)"
+.\" commit 9ecda41acb971ebd07c8fb35faf24005c0baea12
+This makes the ring buffer is written from end to beginning.
+This is to support reading from overwritable ring buffer.
+.TP
+.IR namespaces " (since Linux 4.11)"
+.\" commit e422267322cd319e2695a535e47c5b1feeac45eb
+This enables the generation of
+.B PERF_RECORD_NAMESPACES
+records when a task is entering to a new namespace.
+Each namespace has a combination of device and inode numbers.
+.TP
+.IR ksymbol " (since Linux 5.0)"
+.\" commit 76193a94522f1d4edf2447a536f3f796ce56343b
+This enables the generation of
+.B PERF_RECORD_KSYMBOL
+records when a new kernel symbols are registered or unregistered.
+This is analyzing dynamic kernel functions like eBPF.
+.TP
+.IR bpf_event " (since Linux 5.0)"
+.\" commit 6ee52e2a3fe4ea35520720736e6791df1fb67106
+This enables the generation of
+.B PERF_RECORD_BPF_EVENT
+records when a eBPF program is loaded or unloaded.
+.IR auxevent " (since Linux 5.4)"
+.\" commit ab43762ef010967e4ccd53627f70a2eecbeafefb
+This allows normal (non-AUX) events to generate data for AUX events
+if the hardware supports it.
+.IR cgroup " (since Linux 5.7)"
+.\" commit 96aaab686505c449e24d76e76507290dcc30e008
+This enables the generation of
+.B PERF_RECORD_CGROUP
+records when a new cgroup is created (and activated).
+.TR
+.IR text_poke " (since Linux 5.8)"
+.\" commit e17d43b93e544f5016c0251d2074c15568d5d963
+This enables the generation of
+.B PERF_RECORD_TEXT_POKE
+records when there's a changes to the kernel text
+(i.e. self-modifying code).
+.TP
.IR "wakeup_events" ", " "wakeup_watermark"
This union sets how many samples
.RI ( wakeup_events )
@@ -2101,7 +2165,7 @@ struct {
u64 nr; /* if PERF_SAMPLE_CALLCHAIN */
u64 ips[nr]; /* if PERF_SAMPLE_CALLCHAIN */
u32 size; /* if PERF_SAMPLE_RAW */
- char data[size]; /* if PERF_SAMPLE_RAW */
+ char data[size]; /* if PERF_SAMPLE_RAW */
u64 bnr; /* if PERF_SAMPLE_BRANCH_STACK */
struct perf_branch_entry lbr[bnr];
/* if PERF_SAMPLE_BRANCH_STACK */
@@ -2118,6 +2182,8 @@ struct {
u64 abi; /* if PERF_SAMPLE_REGS_INTR */
u64 regs[weight(mask)];
/* if PERF_SAMPLE_REGS_INTR */
+ u64 phys_addr; /* if PERF_SAMPLE_PHYS_ADDR */
+ u64 cgroup; /* if PERF_SAMPLE_CGROUP */
};
.EE
.in
@@ -2744,6 +2810,201 @@ or next (if switching out) process on the CPU.
The thread ID of the previous (if switching in)
or next (if switching out) thread on the CPU.
.RE
+.TP
+.BR PERF_RECORD_NAMESPACES " (since Linux 4.11)"
+.\" commit e422267322cd319e2695a535e47c5b1feeac45eb
+This record includes various namespace information of a process.
+.RS
+.PP
+.in +4n
+.EX
+struct {
+ struct perf_event_header header;
+ u32 pid;
+ u32 tid;
+ u64 nr_namespaces;
+ struct { u64 dev, inode } [nr_namespaces];
+ struct sample_id sample_id;
+};
+.EE
+.in
+.TP
+.I pid
+is the process ID
+.TP
+.I tid
+is the thread ID
+.TP
+.I nr_namespace
+is the number of namespaces in this record
+.PP
+Each namespace has
+.I dev
+and
+.I inode
+fields and is recorded in the
+fixed position like below:
+.TP
+.BR NET_NS_INDEX = 0
+Network namespace
+.TP
+.BR UTS_NS_INDEX = 1
+UTS namespace
+.TP
+.BR IPC_NS_INDEX = 2
+IPC namespace
+.TP
+.BR PID_NS_INDEX = 3
+PID namespace
+.TP
+.BR USER_NS_INDEX = 4
+User namespace
+.TP
+.BR MNT_NS_INDEX = 5
+Mount namespace
+.TP
+.BR CGROUP_NS_INDEX = 6
+Cgroup namespace
+.PP
+.RE
+.TP
+.BR PERF_RECORD_KSYMBOL " (since Linux 5.0)"
+.\" commit 76193a94522f1d4edf2447a536f3f796ce56343b
+This record indicates kernel symbol register/unregister events.
+.RS
+.PP
+.in +4n
+.EX
+struct {
+ struct perf_event_header header;
+ u64 addr;
+ u32 len;
+ u16 ksym_type;
+ u16 flags;
+ char name[];
+ struct sample_id sample_id;
+};
+.EE
+.in
+.TP
+.I addr
+is the address of the kernel symbol
+.TP
+.I len
+is the length of the kernel symbol
+.TP
+.I ksym_type
+is the type of the kernel symbol.
+Currently following types are available:
+.RS
+.TP
+.B PERF_RECORD_KSYMBOL_TYPE_BPF
+The kernel symbols is a BPF function.
+.RE
+.TP
+.I flags
+If the
+.B PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER
+is set, then this event is for unregistering the kernel symbol.
+.RE
+.TP
+.BR PERF_RECORD_BPF_EVENT " (since Linux 5.0)"
+.\" commit 6ee52e2a3fe4ea35520720736e6791df1fb67106
+This record indicates BPF program is loaded or unloaded.
+.RS
+.PP
+.in +4n
+.EX
+struct {
+ struct perf_event_header header;
+ u16 type;
+ u16 flags;
+ u32 id;
+ u8 tag[BPF_TAG_SIZE];
+ struct sample_id sample_id;
+};
+.EE
+.in
+.TP
+.I type
+is one of the following values:
+.RS
+.TP
+.B PERF_BPF_EVENT_PROG_LOAD
+A BPF program is loaded
+.TP
+.B PERF_BPF_EVENT_PROG_UNLOAD
+A BPF program is unloaded
+.RE
+.TP
+.I id
+is the id of the BPF program.
+.TP
+.I tag
+is the tag of the BPF program.
+Currently,
+.B BPF_TAG_SIZE
+is defined as 8.
+.RE
+.TP
+.BR PERF_RECORD_CGROUP " (since Linux 5.7)"
+.\" commit 96aaab686505c449e24d76e76507290dcc30e008
+This record indicates a new cgroup is created and activated.
+.RS
+.PP
+.in +4n
+.EX
+struct {
+ struct perf_event_header header;
+ u64 id;
+ char path[];
+ struct sample_id sample_id;
+};
+.EE
+.in
+.TP
+.I id
+is the cgroup identifier.
+This can be also retreived by
+.BR name_to_handle_at (2)
+on the cgroup path (as a file handle).
+.TP
+.I path
+is the path of the cgroup from the root.
+.RE
+.TP
+.BR PERF_RECORD_TEXT_POKE " (since Linux 5.8)"
+.\" commit e17d43b93e544f5016c0251d2074c15568d5d963
+This record indicates a change in the kernel text.
+This includes addition and removal of the text
+and the corresponding length is zero in this case.
+.RS
+.PP
+.in +4n
+.EX
+struct {
+ struct perf_event_header header;
+ u64 addr;
+ u16 old_len;
+ u16 new_len;
+ u8 bytes[];
+ struct sample_id sample_id;
+};
+.EE
+.in
+.TP
+.I addr
+is the address of the change
+.TP
+.I old_len
+is the old length
+.TP
+.I new_len
+is the new length
+.TP
+.I bytes
+contains old bytes immediately followed by new bytes.
+.RE
.RE
.SS Overflow handling
Events can be set to notify when a threshold is crossed,
--
2.28.0