Re: [PATCH v5 00/20] Introduce threaded trace streaming for basic perf record operation
From: Namhyung Kim
Date: Thu May 06 2021 - 02:25:39 EST
Hello,
On Tue, May 4, 2021 at 12:05 AM Alexey Bayduraev
<alexey.v.bayduraev@xxxxxxxxxxxxxxx> wrote:
>
> Changes in v5:
> - fixed leaks in record__init_thread_masks_spec()
> - fixed leaks after failed realloc
> - replaced "%m" to strerror()
> - added masks examples to the documentation
> - captured Acked-by: tags by Andi Kleen
> - do not allow --thread option for full_auxtrace mode
> - split patch 06/12 to 06/20 and 07/20
> - split patch 08/12 to 09/20 and 10/20
> - split patches 11/12 and 11/12 to 13/20-20/20
>
> v4: https://lore.kernel.org/lkml/6c15adcb-6a9d-320e-70b5-957c4c8b6ff2@xxxxxxxxxxxxxxx/
>
> Changes in v4:
> - renamed 'comm' structure to 'pipes'
> - moved thread fd/maps messages to verbose=2
> - fixed leaks during allocation of thread_data structures
> - fixed leaks during allocation of thread masks
> - fixed possible fails when releasing thread masks
>
> v3: https://lore.kernel.org/lkml/7d197a2d-56e2-896d-bf96-6de0a4db1fb8@xxxxxxxxxxxxxxx/
>
> Changes in v3:
> - avoided skipped redundant patch 3/15
> - applied "data file" and "data directory" terms allover the patch set
> - captured Acked-by: tags by Namhyung Kim
> - avoided braces where don't needed
> - employed thread local variable for serial trace streaming
> - added specs for --thread option - core, socket, numa and user defined
> - added parallel loading of data directory files similar to the prototype [1]
>
> v2: https://lore.kernel.org/lkml/1ec29ed6-0047-d22f-630b-a7f5ccee96b4@xxxxxxxxxxxxxxx/
>
> Changes in v2:
> - explicitly added credit tags to patches 6/15 and 15/15,
> additionally to cites [1], [2]
> - updated description of 3/15 to explicitly mention the reason
> to open data directories in read access mode (e.g. for perf report)
> - implemented fix for compilation error of 2/15
> - explicitly elaborated on found issues to be resolved for
> threaded AUX trace capture
>
> v1: https://lore.kernel.org/lkml/810f3a69-0004-9dff-a911-b7ff97220ae0@xxxxxxxxxxxxxxx/
>
> Patch set provides parallel threaded trace streaming mode for basic
> perf record operation. Provided mode mitigates profiling data losses
> and resolves scalability issues of serial and asynchronous (--aio)
> trace streaming modes on multicore server systems. The design and
> implementation are based on the prototype [1], [2].
>
> Parallel threaded mode executes trace streaming threads that read kernel
> data buffers and write captured data into several data files located at
> data directory. Layout of trace streaming threads and their mapping to data
> buffers to read can be configured using a value of --thread command line
> option. Specification value provides masks separated by colon so the masks
> define cpus to be monitored by one thread and thread affinity mask is
> separated by slash. <cpus mask 1>/<affinity mask 1>:<cpu mask 2>/<affinity mask 2>
> specifies parallel threads layout that consists of two threads with
> corresponding assigned cpus to be monitored. Specification value can be
> a string e.g. "cpu", "core" or "socket" meaning creation of data streaming
> thread for monitoring every cpu, whole core or socket. The option provided
> with no or empty value defaults to "cpu" layout creating data streaming
> thread for every cpu being monitored. Specification masks are filtered
> by the mask provided via -C option.
>
> Parallel streaming mode is compatible with Zstd compression/decompression
> (--compression-level) and external control commands (--control). The mode
> is not enabled for pipe mode. The mode is not enabled for AUX area tracing,
> related and derived modes like --snapshot or --aux-sample. --switch-output-*
> and --timestamp-filename options are not enabled for parallel streaming.
> Initial intent to enable AUX area tracing faced the need to define some
> optimal way to store index data in data directory. --switch-output-* and
> --timestamp-filename use cases are not clear for data directories.
> Asynchronous(--aio) trace streaming and affinity (--affinity) modes are
> mutually exclusive to parallel streaming mode.
>
> Basic analysis of data directories is provided in perf report mode.
> Raw dump and aggregated reports are available for data directories,
> still with no memory consumption optimizations.
Do you have an idea how to improve it?
I have to say again that I don't like merely adding more threads to
record. Yeah, parallelizing the perf record is good, but we have to
think about the perf report (and others) too.
Thanks,
Namhyung
>
> Tested:
>
> tools/perf/perf record -o prof.data --threads -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads= -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads=cpu -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads=core -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads=socket -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads=numa -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads=0-3/3:4-7/4 -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data -C 2,5 --threads=0-3/3:4-7/4 -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data -C 3,4 --threads=0-3/3:4-7/4 -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data -C 0,4,2,6 --threads=core -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data -C 0,4,2,6 --threads=numa -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads -g --call-graph dwarf,4096 -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads -g --call-graph dwarf,4096 --compression-level=3 -- matrix.gcc.g.O3
> tools/perf/perf record -o prof.data --threads -a
> tools/perf/perf record -D -1 -e cpu-cycles -a --control fd:10,11 -- sleep 30
> tools/perf/perf record --threads -D -1 -e cpu-cycles -a --control fd:10,11 -- sleep 30
>
> tools/perf/perf report -i prof.data
> tools/perf/perf report -i prof.data --call-graph=callee
> tools/perf/perf report -i prof.data --stdio --header
> tools/perf/perf report -i prof.data -D --header
>
> [1] git clone https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git -b perf/record_threads
> [2] https://lore.kernel.org/lkml/20180913125450.21342-1-jolsa@xxxxxxxxxx/
>
> ---
>
> Alexey Bayduraev (20):
> perf record: introduce thread affinity and mmap masks
> perf record: introduce thread specific data array
> perf record: introduce thread local variable
> perf record: stop threads in the end of trace streaming
> perf record: start threads in the beginning of trace streaming
> perf record: introduce data file at mmap buffer object
> perf record: introduce data transferred and compressed stats
> perf record: init data file at mmap buffer object
> tools lib: introduce bitmap_intersects() operation
> perf record: introduce --threads=<spec> command line option
> perf record: document parallel data streaming mode
> perf report: output data file name in raw trace dump
> perf session: move reader structure to the top
> perf session: introduce reader_state in reader object
> perf session: introduce reader objects in session object
> perf session: introduce decompressor into trace reader object
> perf session: move init into reader__init function
> perf session: move map/unmap into reader__mmap function
> perf session: load single file for analysis
> perf session: load data directory files for analysis
>
> tools/include/linux/bitmap.h | 11 +
> tools/lib/api/fd/array.c | 17 +
> tools/lib/api/fd/array.h | 1 +
> tools/lib/bitmap.c | 14 +
> tools/perf/Documentation/perf-record.txt | 30 +
> tools/perf/builtin-inject.c | 3 +-
> tools/perf/builtin-record.c | 1066 ++++++++++++++++++++--
> tools/perf/util/evlist.c | 16 +
> tools/perf/util/evlist.h | 1 +
> tools/perf/util/mmap.c | 6 +
> tools/perf/util/mmap.h | 6 +
> tools/perf/util/ordered-events.h | 1 +
> tools/perf/util/record.h | 2 +
> tools/perf/util/session.c | 491 +++++++---
> tools/perf/util/session.h | 5 +
> tools/perf/util/tool.h | 3 +-
> 16 files changed, 1474 insertions(+), 199 deletions(-)
>
> --
> 2.19.0
>