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4d8c1ba079
The enhancements made to timerlat_load.py are intended to improve the script's exception handling.
Summary of the changes:
- Specific exceptions are now caught for CPU affinity and priority
settings, with clearer error messages provided.
- The timerlat file descriptor opening now includes handling for
PermissionError and OSError, with informative messages.
- In the infinite loop, generic exceptions have been replaced with
specific types like KeyboardInterrupt and IOError, improving feedback.
Before:
$ sudo python timerlat_load.py 122
Error setting affinity
After:
$ sudo python timerlat_load.py 122
Error setting affinity: [Errno 22] Invalid argument
Before:
$ sudo python timerlat_load.py 1 -p 950
Error setting priority
After:
$ sudo python timerlat_load.py 1 -p 950
Error setting priority: [Errno 22] Invalid argument
Before:
$ python timerlat_load.py 1
Error opening timerlat fd, did you run timerlat -U?
After:
$ python timerlat_load.py 1
Permission denied. Please check your access rights.
Cc: "lgoncalv@redhat.com" <lgoncalv@redhat.com>
Cc: "jkacur@redhat.com" <jkacur@redhat.com>
Link: https://lore.kernel.org/Q_k1s4hBtUy2px8ou0QKenjEK2_T_LoV8IxAE79aBakBogb-7uHp2fpET3oWtI1t3dy8uKjWeRzQOdKNzIzOOpyM4OjutJOriZ9TrGY6b-g=@protonmail.com
Signed-off-by: Furkan Onder <furkanonder@protonmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
78 lines
2.3 KiB
Python
78 lines
2.3 KiB
Python
#!/usr/bin/env python3
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# SPDX-License-Identifier: GPL-2.0-only
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#
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# Copyright (C) 2024 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@kernel.org>
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#
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# This is a sample code about how to use timerlat's timer by any workload
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# so rtla can measure and provide auto-analysis for the overall latency (IOW
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# the response time) for a task.
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#
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# Before running it, you need to dispatch timerlat with -U option in a terminal.
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# Then # run this script pinned to a CPU on another terminal. For example:
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#
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# timerlat_load.py 1 -p 95
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#
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# The "Timerlat IRQ" is the IRQ latency, The thread latency is the latency
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# for the python process to get the CPU. The Ret from user Timer Latency is
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# the overall latency. In other words, it is the response time for that
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# activation.
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#
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# This is just an example, the load is reading 20MB of data from /dev/full
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# It is in python because it is easy to read :-)
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import argparse
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import sys
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import os
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parser = argparse.ArgumentParser(description='user-space timerlat thread in Python')
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parser.add_argument("cpu", type=int, help='CPU to run timerlat thread')
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parser.add_argument("-p", "--prio", type=int, help='FIFO priority')
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args = parser.parse_args()
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try:
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affinity_mask = {args.cpu}
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os.sched_setaffinity(0, affinity_mask)
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except Exception as e:
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print(f"Error setting affinity: {e}")
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sys.exit(1)
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if args.prio:
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try:
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param = os.sched_param(args.prio)
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os.sched_setscheduler(0, os.SCHED_FIFO, param)
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except Exception as e:
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print(f"Error setting priority: {e}")
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sys.exit(1)
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try:
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timerlat_path = f"/sys/kernel/tracing/osnoise/per_cpu/cpu{args.cpu}/timerlat_fd"
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timerlat_fd = open(timerlat_path, 'r')
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except PermissionError:
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print("Permission denied. Please check your access rights.")
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sys.exit(1)
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except OSError:
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print("Error opening timerlat fd, did you run timerlat -U?")
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sys.exit(1)
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try:
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data_fd = open("/dev/full", 'r')
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except Exception as e:
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print(f"Error opening data fd: {e}")
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sys.exit(1)
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while True:
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try:
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timerlat_fd.read(1)
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data_fd.read(20 * 1024 * 1024)
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except KeyboardInterrupt:
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print("Leaving")
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break
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except IOError as e:
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print(f"I/O error occurred: {e}")
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break
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except Exception as e:
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print(f"Unexpected error: {e}")
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break
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timerlat_fd.close()
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data_fd.close()
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