[tip:perf/urgent] perf script: Flush output stream after events in verbose mode
Commit-ID: 7ee40678af935fb489b0c6cf0f75808175214cd7 Gitweb: https://git.kernel.org/tip/7ee40678af935fb489b0c6cf0f75808175214cd7 Author: Milian Wolff AuthorDate: Sun, 21 Oct 2018 21:14:24 +0200 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 22 Oct 2018 14:27:11 -0300 perf script: Flush output stream after events in verbose mode When the perf script output is written to a terminal stream, the normal output of `perf script` would get buffered, but its debug output would be written directly. This made it quite hard to figure out where a given debug output is coming from. We can improve on this by flushing the output buffer after processing an event. To see the value, compare the following output for a `perf script -v` run: Before this patch: ``` unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 ... lots and lots of verbose debug output cpp-inlining 24617 90229.122036534: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) cpp-inlining 24617 90229.122043974: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) ... ``` After this patch: ``` ... unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) cpp-inlining 24617 90229.122036534: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) cpp-inlining 24617 90229.122043974: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) ... ``` This new output format makes it much easier to use perf script output for debugging purposes, e.g. to investigate broken dwarf unwinding. Signed-off-by: Milian Wolff Acked-by: Jiri Olsa Link: http://lkml.kernel.org/r/20181021191424.16183-2-milian.wo...@kdab.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-script.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index bd468b90801b..ca09b7d2adb7 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1737,6 +1737,9 @@ static void process_event(struct perf_script *script, if (PRINT_FIELD(METRIC)) perf_sample__fprint_metric(script, thread, evsel, sample, fp); + + if (verbose) + fflush(fp); } static struct scripting_ops*scripting_ops;
[tip:perf/urgent] perf script: Flush output stream after events in verbose mode
Commit-ID: 7ee40678af935fb489b0c6cf0f75808175214cd7 Gitweb: https://git.kernel.org/tip/7ee40678af935fb489b0c6cf0f75808175214cd7 Author: Milian Wolff AuthorDate: Sun, 21 Oct 2018 21:14:24 +0200 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 22 Oct 2018 14:27:11 -0300 perf script: Flush output stream after events in verbose mode When the perf script output is written to a terminal stream, the normal output of `perf script` would get buffered, but its debug output would be written directly. This made it quite hard to figure out where a given debug output is coming from. We can improve on this by flushing the output buffer after processing an event. To see the value, compare the following output for a `perf script -v` run: Before this patch: ``` unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 ... lots and lots of verbose debug output cpp-inlining 24617 90229.122036534: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) cpp-inlining 24617 90229.122043974: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) ... ``` After this patch: ``` ... unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) cpp-inlining 24617 90229.122036534: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) unwind: reg 16, val 7faf7dfdc000 unwind: reg 7, val 7ffc80811e30 unwind: find_proc_info dso /usr/lib/ld-2.28.so unwind: reg 6, val 0 unwind: _start:ip = 0x7faf7dfdc000 (0x2000) cpp-inlining 24617 90229.122043974: 1 cycles:uppp: 7faf7dfdc000 _start+0x0 (/usr/lib/ld-2.28.so) ... ``` This new output format makes it much easier to use perf script output for debugging purposes, e.g. to investigate broken dwarf unwinding. Signed-off-by: Milian Wolff Acked-by: Jiri Olsa Link: http://lkml.kernel.org/r/20181021191424.16183-2-milian.wo...@kdab.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-script.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c index bd468b90801b..ca09b7d2adb7 100644 --- a/tools/perf/builtin-script.c +++ b/tools/perf/builtin-script.c @@ -1737,6 +1737,9 @@ static void process_event(struct perf_script *script, if (PRINT_FIELD(METRIC)) perf_sample__fprint_metric(script, thread, evsel, sample, fp); + + if (verbose) + fflush(fp); } static struct scripting_ops*scripting_ops;
