Date: Thu, 25 May 2017 22:41:35 +0000 (UTC) From: Don Lewis <truckman@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r318905 - stable/10/sys/netpfil/ipfw Message-ID: <201705252241.v4PMfZcv063285@repo.freebsd.org>
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Author: truckman Date: Thu May 25 22:41:34 2017 New Revision: 318905 URL: https://svnweb.freebsd.org/changeset/base/318905 Log: MFC r318527 Fix the queue delay estimation in PIE/FQ-PIE when the timestamp (TS) method is used. When packet timestamp is used, the "current_qdelay" keeps storing the last queue delay value calculated in the dequeue function. Therefore, when a burst of packets arrives followed by a pause, the "current_qdelay" will store a high value caused by the burst and stick to that value during the pause because the queue delay measurement is done inside the dequeue function. This causes the drop probability calculation function to calculate high drop probability value instead of zero and prevents the burst allowance mechanism from working properly. Fix this problem by resetting "current_qdelay" inside the drop probability calculation function when the queue length is zero and TS option is used. Submitted by: Rasool Al-Saadi <ralsaadi@swin.edu.au> Modified: stable/10/sys/netpfil/ipfw/dn_aqm_pie.c stable/10/sys/netpfil/ipfw/dn_sched_fq_pie.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/netpfil/ipfw/dn_aqm_pie.c ============================================================================== --- stable/10/sys/netpfil/ipfw/dn_aqm_pie.c Thu May 25 22:39:48 2017 (r318904) +++ stable/10/sys/netpfil/ipfw/dn_aqm_pie.c Thu May 25 22:41:34 2017 (r318905) @@ -211,11 +211,16 @@ calculate_drop_prob(void *x) pprms = pst->parms; prob = pst->drop_prob; - /* calculate current qdelay */ - if (pprms->flags & PIE_DEPRATEEST_ENABLED) { + /* calculate current qdelay using DRE method. + * If TS is used and no data in the queue, reset current_qdelay + * as it stays at last value during dequeue process. + */ + if (pprms->flags & PIE_DEPRATEEST_ENABLED) pst->current_qdelay = ((uint64_t)pst->pq->ni.len_bytes * pst->avg_dq_time) >> PIE_DQ_THRESHOLD_BITS; - } + else + if (!pst->pq->ni.len_bytes) + pst->current_qdelay = 0; /* calculate drop probability */ p = (int64_t)pprms->alpha * Modified: stable/10/sys/netpfil/ipfw/dn_sched_fq_pie.c ============================================================================== --- stable/10/sys/netpfil/ipfw/dn_sched_fq_pie.c Thu May 25 22:39:48 2017 (r318904) +++ stable/10/sys/netpfil/ipfw/dn_sched_fq_pie.c Thu May 25 22:41:34 2017 (r318905) @@ -383,11 +383,16 @@ fq_calculate_drop_prob(void *x) pprms = pst->parms; prob = pst->drop_prob; - /* calculate current qdelay */ - if (pprms->flags & PIE_DEPRATEEST_ENABLED) { + /* calculate current qdelay using DRE method. + * If TS is used and no data in the queue, reset current_qdelay + * as it stays at last value during dequeue process. + */ + if (pprms->flags & PIE_DEPRATEEST_ENABLED) pst->current_qdelay = ((uint64_t)q->stats.len_bytes * pst->avg_dq_time) >> PIE_DQ_THRESHOLD_BITS; - } + else + if (!q->stats.len_bytes) + pst->current_qdelay = 0; /* calculate drop probability */ p = (int64_t)pprms->alpha *
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