From 7cd468a3d7dee7d6c92f69a0bb7061ae208ec727 Mon Sep 17 00:00:00 2001 From: Damjan Marion Date: Mon, 19 Dec 2016 23:05:39 +0100 Subject: Reorganize source tree to use single autotools instance Change-Id: I7b51f88292e057c6443b12224486f2d0c9f8ae23 Signed-off-by: Damjan Marion --- src/vppinfra/time.c | 226 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 src/vppinfra/time.c (limited to 'src/vppinfra/time.c') diff --git a/src/vppinfra/time.c b/src/vppinfra/time.c new file mode 100644 index 00000000000..2bdb9da4b39 --- /dev/null +++ b/src/vppinfra/time.c @@ -0,0 +1,226 @@ +/* + * Copyright (c) 2015 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +/* + Copyright (c) 2005 Eliot Dresselhaus + + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + "Software"), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +*/ + +#include +#include +#include +#include + +#ifdef CLIB_UNIX + +#include +#include +#include + +/* Not very accurate way of determining cpu clock frequency + for unix. Better to use /proc/cpuinfo on linux. */ +static f64 +estimate_clock_frequency (f64 sample_time) +{ + /* Round to nearest 100KHz. */ + const f64 round_to_units = 100e5; + + f64 time_now, time_start, time_limit, freq; + u64 ifreq, t[2]; + + time_start = time_now = unix_time_now (); + time_limit = time_now + sample_time; + t[0] = clib_cpu_time_now (); + while (time_now < time_limit) + time_now = unix_time_now (); + t[1] = clib_cpu_time_now (); + + freq = (t[1] - t[0]) / (time_now - time_start); + ifreq = flt_round_nearest (freq / round_to_units); + freq = ifreq * round_to_units; + + return freq; +} + +/* Fetch cpu frequency via parseing /proc/cpuinfo. + Only works for Linux. */ +static f64 +clock_frequency_from_proc_filesystem (void) +{ + f64 cpu_freq = 1e9; /* better than 40... */ + f64 ppc_timebase = 0; /* warnings be gone */ + int fd; + unformat_input_t input; + +/* $$$$ aarch64 kernel doesn't report "cpu MHz" */ +#if defined(__aarch64__) + return 0.0; +#endif + + cpu_freq = 0; + fd = open ("/proc/cpuinfo", 0); + if (fd < 0) + return cpu_freq; + + unformat_init_unix_file (&input, fd); + + ppc_timebase = 0; + while (unformat_check_input (&input) != UNFORMAT_END_OF_INPUT) + { + if (unformat (&input, "cpu MHz : %f", &cpu_freq)) + cpu_freq *= 1e6; + else if (unformat (&input, "timebase : %f", &ppc_timebase)) + ; + else + unformat_skip_line (&input); + } + + unformat_free (&input); + + close (fd); + + /* Override CPU frequency with time base for PPC. */ + if (ppc_timebase != 0) + cpu_freq = ppc_timebase; + + return cpu_freq; +} + +/* Fetch cpu frequency via reading /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq + Only works for Linux. */ +static f64 +clock_frequency_from_sys_filesystem (void) +{ + f64 cpu_freq; + int fd; + unformat_input_t input; + + /* Time stamp always runs at max frequency. */ + cpu_freq = 0; + fd = open ("/sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq", 0); + if (fd < 0) + goto done; + + unformat_init_unix_file (&input, fd); + unformat (&input, "%f", &cpu_freq); + cpu_freq *= 1e3; /* measured in kHz */ + unformat_free (&input); + close (fd); +done: + return cpu_freq; +} + +f64 +os_cpu_clock_frequency (void) +{ + f64 cpu_freq; + + if (clib_cpu_supports_invariant_tsc ()) + return estimate_clock_frequency (1e-3); + + /* First try /sys version. */ + cpu_freq = clock_frequency_from_sys_filesystem (); + if (cpu_freq != 0) + return cpu_freq; + + /* Next try /proc version. */ + cpu_freq = clock_frequency_from_proc_filesystem (); + if (cpu_freq != 0) + return cpu_freq; + + /* If /proc/cpuinfo fails (e.g. not running on Linux) fall back to + gettimeofday based estimated clock frequency. */ + return estimate_clock_frequency (1e-3); +} + +#endif /* CLIB_UNIX */ + +/* Initialize time. */ +void +clib_time_init (clib_time_t * c) +{ + memset (c, 0, sizeof (c[0])); + c->clocks_per_second = os_cpu_clock_frequency (); + c->seconds_per_clock = 1 / c->clocks_per_second; + c->log2_clocks_per_second = min_log2_u64 ((u64) c->clocks_per_second); + + /* Initially verify frequency every sec */ + c->log2_clocks_per_frequency_verify = c->log2_clocks_per_second; + + c->last_verify_reference_time = unix_time_now (); + c->last_cpu_time = clib_cpu_time_now (); + c->init_cpu_time = c->last_verify_cpu_time = c->last_cpu_time; +} + +void +clib_time_verify_frequency (clib_time_t * c) +{ + f64 now_reference = unix_time_now (); + f64 dtr = now_reference - c->last_verify_reference_time; + f64 dtr_max; + u64 dtc = c->last_cpu_time - c->last_verify_cpu_time; + f64 round_units = 100e5; + + c->last_verify_cpu_time = c->last_cpu_time; + c->last_verify_reference_time = now_reference; + + /* + * Is the reported reference interval non-positive, + * or off by a factor of two - or 8 seconds - whichever is larger? + * Someone reset the clock behind our back. + */ + dtr_max = (f64) (2ULL << c->log2_clocks_per_frequency_verify) / + (f64) (1ULL << c->log2_clocks_per_second); + dtr_max = dtr_max > 8.0 ? dtr_max : 8.0; + + if (dtr <= 0.0 || dtr > dtr_max) + { + c->log2_clocks_per_frequency_verify = c->log2_clocks_per_second; + return; + } + + c->clocks_per_second = + flt_round_nearest ((f64) dtc / (dtr * round_units)) * round_units; + c->seconds_per_clock = 1 / c->clocks_per_second; + + /* Double time between verifies; max at 64 secs ~ 1 minute. */ + if (c->log2_clocks_per_frequency_verify < c->log2_clocks_per_second + 6) + c->log2_clocks_per_frequency_verify += 1; +} + +/* + * fd.io coding-style-patch-verification: ON + * + * Local Variables: + * eval: (c-set-style "gnu") + * End: + */ -- cgit 1.2.3-korg