"""
Function tracer profiler for autotest.
:author: David Sharp (dhsharp@google.com)
"""
import logging
import os
import signal
import time
from autotest.client import profiler, utils
from autotest.client.shared import error
[docs]class ftrace(profiler.profiler):
"""
ftrace profiler for autotest. It builds ftrace from souce and runs
trace-cmd with configurable parameters.
@see: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
"""
version = 1
mountpoint = '/sys/kernel/debug'
tracing_dir = os.path.join(mountpoint, 'tracing')
@staticmethod
[docs] def join_command(cmd):
"""
Shell escape the command for BgJob. grmbl.
:param cmd: Command list.
"""
result = []
for arg in cmd:
arg = '"%s"' % utils.sh_escape(arg)
result += [arg]
return ' '.join(result)
[docs] def setup(self, tarball='trace-cmd.tar.bz2', **kwargs):
"""
Build and install trace-cmd from source.
The tarball was obtained by checking the git repo at 09-14-2010,
removing the Documentation and the .git folders, and compressing
it.
:param tarball: Path to trace-cmd tarball.
:param **kwargs: Dictionary with additional parameters.
"""
self.tarball = utils.unmap_url(self.bindir, tarball, self.tmpdir)
utils.extract_tarball_to_dir(self.tarball, self.srcdir)
os.chdir(self.srcdir)
utils.make("prefix='%s'" % self.builddir)
utils.make("prefix='%s' install" % self.builddir)
[docs] def initialize(self, tracepoints, buffer_size_kb=1408, **kwargs):
"""
Initialize ftrace profiler.
:param tracepoints: List containing a mix of tracpoint names and
(tracepoint name, filter) tuples. Tracepoint names are as
accepted by trace-cmd -e, eg "syscalls", or
"syscalls:sys_enter_read". Filters are as accepted by
trace-cmd -f, eg "((sig >= 10 && sig < 15) || sig == 17)"
:param buffer_size_kb: Set the size of the ring buffer (per cpu).
"""
self.job.require_gcc()
self.trace_cmd_args = ['-b', str(buffer_size_kb)]
for tracepoint in tracepoints:
if isinstance(tracepoint, tuple):
tracepoint, event_filter = tracepoint
else:
event_filter = None
self.trace_cmd_args += ['-e', tracepoint]
if event_filter:
self.trace_cmd_args += ['-f', event_filter]
self.builddir = os.path.join(self.bindir, 'build')
if not os.path.isdir(self.builddir):
os.makedirs(self.builddir)
self.trace_cmd = os.path.join(self.builddir, 'bin', 'trace-cmd')
[docs] def start(self, test):
"""
Start ftrace profiler
:param test: Autotest test in which the profiler will operate on.
"""
# Make sure debugfs is mounted and tracing disabled.
utils.system('%s reset' % self.trace_cmd)
output_dir = os.path.join(test.profdir, 'ftrace')
if not os.path.isdir(output_dir):
os.makedirs(output_dir)
self.output = os.path.join(output_dir, 'trace.dat')
cmd = [self.trace_cmd, 'record', '-o', self.output]
cmd += self.trace_cmd_args
self.record_job = utils.BgJob(self.join_command(cmd),
stderr_tee=utils.TEE_TO_LOGS)
# Wait for tracing to be enabled. If trace-cmd dies before enabling
# tracing, then there was a problem.
tracing_on = os.path.join(self.tracing_dir, 'tracing_on')
while (self.record_job.sp.poll() is None and
utils.read_file(tracing_on).strip() != '1'):
time.sleep(0.1)
if self.record_job.sp.poll() is not None:
utils.join_bg_jobs([self.record_job])
raise error.CmdError(self.record_job.command,
self.record_job.sp.returncode,
'trace-cmd exited early.')
[docs] def stop(self, test):
"""
Stop ftrace profiler.
:param test: Autotest test in which the profiler will operate on.
"""
os.kill(self.record_job.sp.pid, signal.SIGINT)
utils.join_bg_jobs([self.record_job])
# shrink the buffer to free memory.
utils.system('%s reset -b 1' % self.trace_cmd)
# compress output
utils.system('bzip2 %s' % self.output)
compressed_output = self.output + '.bz2'
# if the compressed trace file is large (10MB), just delete it.
compressed_output_size = os.path.getsize(compressed_output)
if compressed_output_size > 10 * 1024 * 1024:
logging.warn('Deleting large trace file %s (%d bytes)',
compressed_output, compressed_output_size)
os.remove(compressed_output)
# remove per-cpu files in case trace-cmd died.
utils.system('rm -f %s.cpu*' % self.output)