43 lines
1.0 KiB
C
43 lines
1.0 KiB
C
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#ifndef __SCX_RAVG_BPF_H__
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#define __SCX_RAVG_BPF_H__
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/*
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* Running average helpers to be used in BPF progs. Assumes vmlinux.h has
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* already been included.
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*/
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enum ravg_consts {
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RAVG_VAL_BITS = 44, /* input values are 44bit */
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RAVG_FRAC_BITS = 20, /* 1048576 is 1.0 */
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};
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/*
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* Running avg mechanism. Accumulates values between 0 and RAVG_MAX_VAL in
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* arbitrary time intervals. The accumulated values are halved every half_life
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* with each period starting when the current time % half_life is 0. Zeroing is
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* enough for initialization.
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*
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* See ravg_accumulate() and ravg_read() for more details.
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*/
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struct ravg_data {
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/* current value */
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u64 val;
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/*
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* The timestamp of @val. The latest completed seq #:
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*
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* (val_at / half_life) - 1
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*/
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u64 val_at;
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/* running avg as of the latest completed seq */
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u64 old;
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/*
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* Accumulated value of the current period. Input value is 48bits and we
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* normalize half-life to 16bit, so it should fit in an u64.
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*/
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u64 cur;
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};
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#endif /* __SCX_RAVG_BPF_H__ */
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