c386d11765
A new tempcomp directive can be used to specify a file for reading current temperature, update interval and compensation coefficients. The clock frequency corrections are applied in local module and are invisible in upper layers. The measurements and corrections can be logged to tempcomp.log file.
101 lines
2.4 KiB
C
101 lines
2.4 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2010
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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Routines implementing temperature compensation.
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*/
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#include "conf.h"
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#include "local.h"
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#include "memory.h"
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#include "util.h"
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#include "logging.h"
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#include "sched.h"
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#include "tempcomp.h"
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static SCH_TimeoutID timeout_id;
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static LOG_FileID logfileid;
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static char *filename;
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static double update_interval;
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static double T0, k0, k1, k2;
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static void
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read_timeout(void *arg)
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{
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FILE *f;
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double temp, comp;
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f = fopen(filename, "r");
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if (f && fscanf(f, "%lf", &temp) == 1) {
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comp = k0 + (temp - T0) * k1 + (temp - T0) * (temp - T0) * k2;
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/* Don't allow corrections above 10 ppm */
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if (fabs(comp) < 10.0) {
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LCL_SetTempComp(comp);
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if (logfileid != -1) {
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struct timeval now;
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LCL_ReadCookedTime(&now, NULL);
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LOG_FileWrite(logfileid, "%s %11.4e %11.4e",
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UTI_TimeToLogForm(now.tv_sec), temp, comp);
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}
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}
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}
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if (f)
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fclose(f);
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timeout_id = SCH_AddTimeoutByDelay(update_interval, read_timeout, NULL);
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}
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void
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TMC_Initialise(void)
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{
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CNF_GetTempComp(&filename, &update_interval, &T0, &k0, &k1, &k2);
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if (filename == NULL)
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return;
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if (update_interval <= 0.0)
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update_interval = 1.0;
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logfileid = CNF_GetLogTempComp() ? LOG_FileOpen("tempcomp",
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" Date (UTC) Time Temp. Comp.")
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: -1;
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read_timeout(NULL);
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}
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void
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TMC_Finalise(void)
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{
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if (filename == NULL)
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return;
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SCH_RemoveTimeout(timeout_id);
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Free(filename);
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}
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