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authorAnita Zhang <the.anitazha@gmail.com>2020-06-04 11:13:29 +0200
committerAnita Zhang <the.anitazha@gmail.com>2020-10-08 01:17:24 +0200
commit510ca79cf2443bba5089f34e1fec2466cf5312ac (patch)
treea2701a5bfb07973a0f2e876a8191fde963fb3741 /src/basic/linux
parentcore: add varlink call to get cgroup paths of units using ManagedOOM*= (diff)
downloadsystemd-510ca79cf2443bba5089f34e1fec2466cf5312ac.tar.xz
systemd-510ca79cf2443bba5089f34e1fec2466cf5312ac.zip
parse-util: add parse_loadavg_fixed_point
Diffstat (limited to 'src/basic/linux')
-rw-r--r--src/basic/linux/loadavg.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/src/basic/linux/loadavg.h b/src/basic/linux/loadavg.h
new file mode 100644
index 0000000000..521a787e8a
--- /dev/null
+++ b/src/basic/linux/loadavg.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SCHED_LOADAVG_H
+#define _LINUX_SCHED_LOADAVG_H
+
+/*
+ * These are the constant used to fake the fixed-point load-average
+ * counting. Some notes:
+ * - 11 bit fractions expand to 22 bits by the multiplies: this gives
+ * a load-average precision of 10 bits integer + 11 bits fractional
+ * - if you want to count load-averages more often, you need more
+ * precision, or rounding will get you. With 2-second counting freq,
+ * the EXP_n values would be 1981, 2034 and 2043 if still using only
+ * 11 bit fractions.
+ */
+extern unsigned long avenrun[]; /* Load averages */
+extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
+
+#define FSHIFT 11 /* nr of bits of precision */
+#define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */
+#define LOAD_FREQ (5*HZ+1) /* 5 sec intervals */
+#define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */
+#define EXP_5 2014 /* 1/exp(5sec/5min) */
+#define EXP_15 2037 /* 1/exp(5sec/15min) */
+
+/*
+ * a1 = a0 * e + a * (1 - e)
+ */
+static inline unsigned long
+calc_load(unsigned long load, unsigned long exp, unsigned long active)
+{
+ unsigned long newload;
+
+ newload = load * exp + active * (FIXED_1 - exp);
+ if (active >= load)
+ newload += FIXED_1-1;
+
+ return newload / FIXED_1;
+}
+
+extern unsigned long calc_load_n(unsigned long load, unsigned long exp,
+ unsigned long active, unsigned int n);
+
+#define LOAD_INT(x) ((x) >> FSHIFT)
+#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
+
+extern void calc_global_load(unsigned long ticks);
+
+#endif /* _LINUX_SCHED_LOADAVG_H */