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If using parallel threads to collect data, perf record needs at least 6 fds
per CPU. (one for sys_perf_event_open, four for pipe msg and ack of the
pipe, see record__thread_data_open_pipes(), and one for open perf.data.XXX)
For an environment with more than 100 cores, if perf record uses both
`-a` and `--threads` options, it is easy to exceed the upper limit of the
file descriptor number, when we run out of them try to increase the limits.
Before:
$ ulimit -n
1024
$ lscpu | grep 'On-line CPU(s)'
On-line CPU(s) list: 0-159
$ perf record --threads -a sleep 1
Failed to create data directory: Too many open files
After:
$ ulimit -n
1024
$ lscpu | grep 'On-line CPU(s)'
On-line CPU(s) list: 0-159
$ perf record --threads -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.394 MB perf.data (1576 samples) ]
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20231013075945.698874-1-yangjihong1@huawei.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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The CPI_STALL_RATIO metric group can be used to present the high
level CPI stall breakdown metrics in powerpc, which will show:
- DISPATCH_STALL_CPI ( Dispatch stall cycles per insn )
- ISSUE_STALL_CPI ( Issue stall cycles per insn )
- EXECUTION_STALL_CPI ( Execution stall cycles per insn )
- COMPLETION_STALL_CPI ( Completion stall cycles per insn )
Commit cf26e043c2a9 ("perf vendor events power10: Add JSON
metric events to present CPI stall cycles in powerpc)" which added
the CPI_STALL_RATIO metric group, also modified
the PMC value used in PM_RUN_INST_CMPL event from PMC4 to PMC5,
to avoid multiplexing of events.
But that got revert in recent changes. Fix this issue by changing
back the PMC value used in PM_RUN_INST_CMPL to PMC5.
Result with the fix:
./perf stat --metric-no-group -M CPI_STALL_RATIO <workload>
Performance counter stats for 'workload':
68,745,426 PM_CMPL_STALL # 0.21 COMPLETION_STALL_CPI
7,692,827 PM_ISSUE_STALL # 0.02 ISSUE_STALL_CPI
322,638,223 PM_RUN_INST_CMPL # 0.05 DISPATCH_STALL_CPI
# 0.48 EXECUTION_STALL_CPI
16,858,553 PM_DISP_STALL_CYC
153,880,133 PM_EXEC_STALL
0.089774592 seconds time elapsed
"--metric-no-group" is used for forcing PM_RUN_INST_CMPL to be scheduled
in all group for more accuracy.
Fixes: 7d473f475b2a ("perf vendor events: Move JSON/events to appropriate files for power10 platform")
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Reviewed-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Disha Goel<disgoel@linux.ibm.com>
Cc: maddy@linux.ibm.com
Link: https://lore.kernel.org/r/20231016143110.244255-1-kjain@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Perf test case 111 Check open filename arg using perf trace + vfs_getname
fails on s390. This is caused by a failing function
bpf_probe_read() in file util/bpf_skel/augmented_raw_syscalls.bpf.c.
The root cause is the lookup by address. Function bpf_probe_read()
is used. This function works only for architectures
with ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
On s390 is not possible to determine from the address to which
address space the address belongs to (user or kernel space).
Replace bpf_probe_read() by bpf_probe_read_kernel()
and bpf_probe_read_str() by bpf_probe_read_user_str() to
explicity specify the address space the address refers to.
Output before:
# ./perf trace -eopen,openat -- touch /tmp/111
libbpf: prog 'sys_enter': BPF program load failed: Invalid argument
libbpf: prog 'sys_enter': -- BEGIN PROG LOAD LOG --
reg type unsupported for arg#0 function sys_enter#75
0: R1=ctx(off=0,imm=0) R10=fp0
; int sys_enter(struct syscall_enter_args *args)
0: (bf) r6 = r1 ; R1=ctx(off=0,imm=0) R6_w=ctx(off=0,imm=0)
; return bpf_get_current_pid_tgid();
1: (85) call bpf_get_current_pid_tgid#14 ; R0_w=scalar()
2: (63) *(u32 *)(r10 -8) = r0 ; R0_w=scalar() R10=fp0 fp-8=????mmmm
3: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
;
.....
lines deleted here
.....
23: (bf) r3 = r6 ; R3_w=ctx(off=0,imm=0) R6=ctx(off=0,imm=0)
24: (85) call bpf_probe_read#4
unknown func bpf_probe_read#4
processed 23 insns (limit 1000000) max_states_per_insn 0 \
total_states 2 peak_states 2 mark_read 2
-- END PROG LOAD LOG --
libbpf: prog 'sys_enter': failed to load: -22
libbpf: failed to load object 'augmented_raw_syscalls_bpf'
libbpf: failed to load BPF skeleton 'augmented_raw_syscalls_bpf': -22
....
Output after:
# ./perf test -Fv 111
111: Check open filename arg using perf trace + vfs_getname :
--- start ---
1.085 ( 0.011 ms): touch/320753 openat(dfd: CWD, filename: \
"/tmp/temporary_file.SWH85", \
flags: CREAT|NOCTTY|NONBLOCK|WRONLY, mode: IRUGO|IWUGO) = 3
---- end ----
Check open filename arg using perf trace + vfs_getname: Ok
#
Test with the sleep command shows:
Output before:
# ./perf trace -e *sleep sleep 1.234567890
0.000 (1234.681 ms): sleep/63114 clock_nanosleep(rqtp: \
{ .tv_sec: 0, .tv_nsec: 0 }, rmtp: 0x3ffe0979720) = 0
#
Output after:
# ./perf trace -e *sleep sleep 1.234567890
0.000 (1234.686 ms): sleep/64277 clock_nanosleep(rqtp: \
{ .tv_sec: 1, .tv_nsec: 234567890 }, rmtp: 0x3fff3df9ea0) = 0
#
Fixes: 14e4b9f4289a ("perf trace: Raw augmented syscalls fix libbpf 1.0+ compatibility")
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Co-developed-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: gor@linux.ibm.com
Cc: hca@linux.ibm.com
Cc: sumanthk@linux.ibm.com
Cc: svens@linux.ibm.com
Link: https://lore.kernel.org/r/20231019082642.3286650-1-tmricht@linux.ibm.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
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Yang Jihong
Kajol Jain
Thomas Richter