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Athira Rajeev a8aade318d perf stat: Fix printing os->prefix in CSV metrics output
[ Upstream commit ad353b710c7493df3d4fc2d3a51819126bed2e81 ]

'perf stat' with CSV output option prints an extra empty string as first
field in metrics output line.  Sample output below:

	# ./perf stat -x, --per-socket -a -C 1 ls
	S0,1,1.78,msec,cpu-clock,1785146,100.00,0.973,CPUs utilized
	S0,1,26,,context-switches,1781750,100.00,0.015,M/sec
	S0,1,1,,cpu-migrations,1780526,100.00,0.561,K/sec
	S0,1,1,,page-faults,1779060,100.00,0.561,K/sec
	S0,1,875807,,cycles,1769826,100.00,0.491,GHz
	S0,1,85281,,stalled-cycles-frontend,1767512,100.00,9.74,frontend cycles idle
	S0,1,576839,,stalled-cycles-backend,1766260,100.00,65.86,backend cycles idle
	S0,1,288430,,instructions,1762246,100.00,0.33,insn per cycle
====>	,S0,1,,,,,,,2.00,stalled cycles per insn

The above command line uses field separator as "," via "-x," option and
per-socket option displays socket value as first field. But here the
last line for "stalled cycles per insn" has "," in the beginning.

Sample output using interval mode:

	# ./perf stat -I 1000 -x, --per-socket -a -C 1 ls
	0.001813453,S0,1,1.87,msec,cpu-clock,1872052,100.00,0.002,CPUs utilized
	0.001813453,S0,1,2,,context-switches,1868028,100.00,1.070,K/sec
	------
	0.001813453,S0,1,85379,,instructions,1856754,100.00,0.32,insn per cycle
====>	0.001813453,,S0,1,,,,,,,1.34,stalled cycles per insn

Above result also has an extra CSV separator after
the timestamp. Patch addresses extra field separator
in the beginning of the metric output line.

The counter stats are displayed by function
"perf_stat__print_shadow_stats" in code
"util/stat-shadow.c". While printing the stats info
for "stalled cycles per insn", function "new_line_csv"
is used as new_line callback.

The new_line_csv function has check for "os->prefix"
and if prefix is not null, it will be printed along
with cvs separator.
Snippet from "new_line_csv":
	if (os->prefix)
               fprintf(os->fh, "%s%s", os->prefix, config->csv_sep);

Here os->prefix gets printed followed by ","
which is the cvs separator. The os->prefix is
used in interval mode option ( -I ), to print
time stamp on every new line. But prefix is
already set to contain CSV separator when used
in interval mode for CSV option.

Reference: Function "static void print_interval"
Snippet:
	sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, config->csv_sep);

Also if prefix is not assigned (if not used with
-I option), it gets set to empty string.
Reference: function printout() in util/stat-display.c
Snippet:
	.prefix = prefix ? prefix : "",

Since prefix already set to contain cvs_sep in interval
option, patch removes printing config->csv_sep in
new_line_csv function to avoid printing extra field.

After the patch:

	# ./perf stat -x, --per-socket -a -C 1 ls
	S0,1,2.04,msec,cpu-clock,2045202,100.00,1.013,CPUs utilized
	S0,1,2,,context-switches,2041444,100.00,979.289,/sec
	S0,1,0,,cpu-migrations,2040820,100.00,0.000,/sec
	S0,1,2,,page-faults,2040288,100.00,979.289,/sec
	S0,1,254589,,cycles,2036066,100.00,0.125,GHz
	S0,1,82481,,stalled-cycles-frontend,2032420,100.00,32.40,frontend cycles idle
	S0,1,113170,,stalled-cycles-backend,2031722,100.00,44.45,backend cycles idle
	S0,1,88766,,instructions,2030942,100.00,0.35,insn per cycle
	S0,1,,,,,,,1.27,stalled cycles per insn

Fixes: 92a61f6412 ("perf stat: Implement CSV metrics output")
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Reviewed-By: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20221018085605.63834-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-11-25 17:42:06 +01:00
arch KVM: x86: emulator: update the emulation mode after CR0 write 2022-11-10 17:57:57 +01:00
block block, bfq: protect 'bfqd->queued' by 'bfqd->lock' 2022-11-10 17:57:54 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: akcipher - default implementation for setting a private key 2022-10-26 13:22:45 +02:00
Documentation tracing/histogram: Update document for KEYS_MAX size 2022-11-10 17:57:55 +01:00
drivers drivers: net: xgene: disable napi when register irq failed in xgene_enet_open() 2022-11-25 17:42:06 +01:00
fs xfs: drain the buf delwri queue before xfsaild idles 2022-11-25 17:42:03 +01:00
include capabilities: fix undefined behavior in bit shift for CAP_TO_MASK 2022-11-25 17:42:05 +01:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc ipc: remove memcg accounting for sops objects in do_semtimedop() 2022-11-10 17:57:58 +01:00
kernel kprobe: reverse kp->flags when arm_kprobe failed 2022-11-10 17:57:55 +01:00
lib dyndbg: let query-modname override actual module name 2022-10-26 13:22:37 +02:00
LICENSES
mm mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages 2022-11-03 23:56:54 +09:00
net tipc: fix the msg->req tlv len check in tipc_nl_compat_name_table_dump_header 2022-11-25 17:42:05 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts kbuild: remove the target in signal traps when interrupted 2022-10-26 13:22:46 +02:00
security capabilities: fix potential memleak on error path from vfs_getxattr_alloc() 2022-11-10 17:57:55 +01:00
sound ALSA: usb-audio: Add quirks for MacroSilicon MS2100/MS2106 devices 2022-11-10 17:57:56 +01:00
tools perf stat: Fix printing os->prefix in CSV metrics output 2022-11-25 17:42:06 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
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MAINTAINERS MAINTAINERS: add Chandan as xfs maintainer for 5.4.y 2022-09-28 11:03:58 +02:00
Makefile Linux 5.4.224 2022-11-10 17:57:58 +01:00
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