Messages in this thread | | | From | kan.liang@intel ... | Subject | [PATCH 00/10] new mmap_read interfaces for ring buffer | Date | Tue, 10 Oct 2017 10:20:13 -0700 |
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From: Kan Liang <kan.liang@intel.com>
The mmap_read interfaces for ring buffer has some issues - Not well organized. For example, perf record maintains some codes in builtin-record.c. Other perf tools use perf_mmap__read* functions to access ring buffer. Some of the codes should be shared. - Only support forward mode. Although there is perf_mmap__read_backward, no one use it. It's not well maintained. But perf top need to switch to overwrite backward mode for good performance. - There is bug found on overwrite backward mode.
The patch series will move all the mmap_read related code to evlist.c, and provide new standard interfaces to access ring buffer. The new interfaces include, perf_evlist__mmap_read_init //wrapper of perf_mmap__read_init perf_mmap__read_init //Initialization and calculate the range perf_mmap__read_to_file //read the ring buffer and write to file perf_mmap__read_event //read the event in specified range perf_mmap__read_done //Update the md->prev for later use
For perf record, it needs to read all available data in ring buffer and write them to perf.data file. It can be done as below, perf_mmap__read_init perf_mmap__read_to_file perf_mmap__consume
For other perf tools, it needs to read and process events one by one. It can be done as below, perf_mmap__read_init while (event = perf_mmap__read_event) { //process the event perf_mmap__consume } perf_mmap__read_done
All the stale interfaces will be removed, which include perf_evlist__mmap_read perf_evlist__mmap_read_forward perf_evlist__mmap_read_backward perf_evlist__mmap_read_catchup perf_mmap__read_catchup perf_mmap__read_forward perf_mmap__read_backward
The patch series only changes the interfaces. It doesn't change the core perf_mmap__read function. There is no functional change.
Kan Liang (10): perf record: new interfaces to read ring buffer to file perf tool: fix: Don't discard prev in backward mode perf tool: new functions to read event from ring buffer perf tool: perf_mmap__read_init wraper for evlist perf top: apply new mmap_read interfaces perf trace: apply new mmap_read interfaces perf kvm: apply new mmap_read interfaces perf python: apply new mmap_read interfaces perf tests: apply new mmap_read interfaces perf tool: remove stale mmap_read interfaces
tools/perf/arch/x86/tests/perf-time-to-tsc.c | 9 +- tools/perf/builtin-kvm.c | 10 +- tools/perf/builtin-record.c | 111 +++--------- tools/perf/builtin-top.c | 9 +- tools/perf/builtin-trace.c | 9 +- tools/perf/tests/backward-ring-buffer.c | 10 +- tools/perf/tests/bpf.c | 10 +- tools/perf/tests/code-reading.c | 8 +- tools/perf/tests/keep-tracking.c | 8 +- tools/perf/tests/mmap-basic.c | 9 +- tools/perf/tests/openat-syscall-tp-fields.c | 9 +- tools/perf/tests/perf-record.c | 9 +- tools/perf/tests/sw-clock.c | 8 +- tools/perf/tests/switch-tracking.c | 8 +- tools/perf/tests/task-exit.c | 8 +- tools/perf/util/evlist.c | 244 +++++++++++++++++---------- tools/perf/util/evlist.h | 31 ++-- tools/perf/util/python.c | 9 +- 18 files changed, 314 insertions(+), 205 deletions(-)
-- 2.5.5
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