[PATCH v5 0/4] perf stat: Introduce iostat mode to provide I/O performance metrics

From: Alexander Antonov
Date: Wed Mar 24 2021 - 10:31:46 EST


The previous version can be found at:
v4: https://lkml.kernel.org/r/20210203135830.38568-1-alexander.antonov@xxxxxxxxxxxxxxx/
Changes in this revision are:
v4 -> v5:
- Addressed comments from Namhyung Kim:
1. Removed AGGR_PCIE_PORT aggregation mode
2. Added iostat_prepare() function
3. Moved implementation specific fprintf() calls to separate x86-related function
4. Fixed code-related issues
- Moved __weak iostat's functions to separate util/iostat.c file

The previous version can be found at:
v3: https://lkml.kernel.org/r/20210126080619.30275-1-alexander.antonov@xxxxxxxxxxxxxxx/
Changes in this revision are:
v3 -> v4:
- Addressed comment from Namhyung Kim:
1. Removed NULL-termination of root ports list

The previous version can be found at:
v2: https://lkml.kernel.org/r/20201223130320.3930-1-alexander.antonov@xxxxxxxxxxxxxxx

Changes in this revision are:
v2 -> v3:
- Addressed comments from Namhyung Kim:
1. Removed perf_device pointer from evsel structure. Use priv field instead
2. Renamed 'iiostat' to 'iostat'
3. Renamed 'show' mode to 'list' mode
4. Renamed iiostat_delete_root_ports() to iiostat_release() and
iostat_show_root_ports() to iostat_list()

The previous version can be found at:
v1: https://lkml.kernel.org/r/20201210090340.14358-1-alexander.antonov@xxxxxxxxxxxxxxx

Changes in this revision are:
v1 -> v2:
- Addressed comment from Arnaldo Carvalho de Melo:
1. Using 'perf iiostat' subcommand instead of 'perf stat --iiostat':
- Added perf-iiostat.sh script to use short command
- Updated manual pages to get help for 'perf iiostat'
- Added 'perf-iiostat' to perf's gitignore file

Mode is intended to provide four I/O performance metrics in MB per each
root port:
- Inbound Read: I/O devices below root port read from the host memory
- Inbound Write: I/O devices below root port write to the host memory
- Outbound Read: CPU reads from I/O devices below root port
- Outbound Write: CPU writes to I/O devices below root port

Each metric requiries only one uncore event which increments at every 4B
transfer in corresponding direction. The formulas to compute metrics
are generic:
#EventCount * 4B / (1024 * 1024)

Note: iostat introduces new perf data aggregation mode - per PCIe root port
hence -e and -M options are not supported.

Usage examples:

1. List all PCIe root ports (example for 2-S platform):
$ perf iostat list
S0-uncore_iio_0<0000:00>
S1-uncore_iio_0<0000:80>
S0-uncore_iio_1<0000:17>
S1-uncore_iio_1<0000:85>
S0-uncore_iio_2<0000:3a>
S1-uncore_iio_2<0000:ae>
S0-uncore_iio_3<0000:5d>
S1-uncore_iio_3<0000:d7>

2. Collect metrics for all PCIe root ports:
$ perf iostat -- dd if=/dev/zero of=/dev/nvme0n1 bs=1M oflag=direct
357708+0 records in
357707+0 records out
375083606016 bytes (375 GB, 349 GiB) copied, 215.974 s, 1.7 GB/s

Performance counter stats for 'system wide':

port Inbound Read(MB) Inbound Write(MB) Outbound Read(MB) Outbound Write(MB)
0000:00 1 0 2 3
0000:80 0 0 0 0
0000:17 352552 43 0 21
0000:85 0 0 0 0
0000:3a 3 0 0 0
0000:ae 0 0 0 0
0000:5d 0 0 0 0
0000:d7 0 0 0 0

3. Collect metrics for comma separated list of PCIe root ports:
$ perf iostat 0000:17,0:3a -- dd if=/dev/zero of=/dev/nvme0n1 bs=1M oflag=direct
357708+0 records in
357707+0 records out
375083606016 bytes (375 GB, 349 GiB) copied, 197.08 s, 1.9 GB/s

Performance counter stats for 'system wide':

port Inbound Read(MB) Inbound Write(MB) Outbound Read(MB) Outbound Write(MB)
0000:17 358559 44 0 22
0000:3a 3 2 0 0

197.081983474 seconds time elapsed

Alexander Antonov (4):
perf stat: Basic support for iostat in perf
perf stat: Helper functions for PCIe root ports list in iostat mode
perf stat: Enable iostat mode for x86 platforms
perf: Update .gitignore file

tools/perf/.gitignore | 1 +
tools/perf/Documentation/perf-iostat.txt | 88 +++++
tools/perf/Makefile.perf | 5 +-
tools/perf/arch/x86/util/Build | 1 +
tools/perf/arch/x86/util/iostat.c | 470 +++++++++++++++++++++++
tools/perf/builtin-stat.c | 21 +-
tools/perf/command-list.txt | 1 +
tools/perf/perf-iostat.sh | 12 +
tools/perf/util/Build | 1 +
tools/perf/util/iostat.c | 53 +++
tools/perf/util/iostat.h | 47 +++
tools/perf/util/stat-display.c | 40 +-
tools/perf/util/stat-shadow.c | 5 +-
tools/perf/util/stat.h | 1 +
14 files changed, 733 insertions(+), 13 deletions(-)
create mode 100644 tools/perf/Documentation/perf-iostat.txt
create mode 100644 tools/perf/arch/x86/util/iostat.c
create mode 100644 tools/perf/perf-iostat.sh
create mode 100644 tools/perf/util/iostat.c
create mode 100644 tools/perf/util/iostat.h


base-commit: 6859bc0e78c6a699599cbb21404fdb6c8125da74
--
2.19.1