64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+
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* Copyright © 2019 VMware, Inc. */
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#include "alloc-util.h"
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#include "fileio.h"
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#include "parse-util.h"
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#include "tc-util.h"
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#include "time-util.h"
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static int tc_init(double *ticks_in_usec) {
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uint32_t clock_resolution, ticks_to_usec, usec_to_ticks;
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_cleanup_free_ char *line = NULL;
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double clock_factor;
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int r;
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r = read_one_line_file("/proc/net/psched", &line);
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if (r < 0)
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return r;
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r = sscanf(line, "%08x%08x%08x", &ticks_to_usec, &usec_to_ticks, &clock_resolution);
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if (r < 3)
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return -EIO;
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clock_factor = (double) clock_resolution / USEC_PER_SEC;
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*ticks_in_usec = (double) ticks_to_usec / usec_to_ticks * clock_factor;
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return 0;
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}
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int tc_time_to_tick(usec_t t, uint32_t *ret) {
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static double ticks_in_usec = -1;
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usec_t a;
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int r;
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assert(ret);
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if (ticks_in_usec < 0) {
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r = tc_init(&ticks_in_usec);
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if (r < 0)
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return r;
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}
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a = t * ticks_in_usec;
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if (a > UINT32_MAX)
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return -ERANGE;
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*ret = a;
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return 0;
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}
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int parse_tc_percent(const char *s, uint32_t *percent) {
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int r;
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assert(s);
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assert(percent);
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r = parse_permille(s);
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if (r < 0)
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return r;
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*percent = (double) r / 1000 * UINT32_MAX;
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return 0;
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}
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