aboutsummaryrefslogtreecommitdiffstats
path: root/net/dccp/ccids/lib/tfrc.h
diff options
context:
space:
mode:
Diffstat (limited to 'net/dccp/ccids/lib/tfrc.h')
-rw-r--r--net/dccp/ccids/lib/tfrc.h15
1 files changed, 15 insertions, 0 deletions
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index bb47146ac7d1..ede12f53de5a 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -48,6 +48,21 @@ static inline u32 scaled_div32(u64 a, u64 b)
48} 48}
49 49
50/** 50/**
51 * tfrc_scaled_sqrt - Compute scaled integer sqrt(x) for 0 < x < 2^22-1
52 * Uses scaling to improve accuracy of the integer approximation of sqrt(). The
53 * scaling factor of 2^10 limits the maximum @sample to 4e6; this is okay for
54 * clamped RTT samples (dccp_sample_rtt).
55 * Should best be used for expressions of type sqrt(x)/sqrt(y), since then the
56 * scaling factor is neutralised. For this purpose, it avoids returning zero.
57 */
58static inline u16 tfrc_scaled_sqrt(const u32 sample)
59{
60 const unsigned long non_zero_sample = sample ? : 1;
61
62 return int_sqrt(non_zero_sample << 10);
63}
64
65/**
51 * tfrc_ewma - Exponentially weighted moving average 66 * tfrc_ewma - Exponentially weighted moving average
52 * @weight: Weight to be used as damping factor, in units of 1/10 67 * @weight: Weight to be used as damping factor, in units of 1/10
53 */ 68 */