Author: rscheff Date: Thu Jun 4 21:02:24 2020 New Revision: 361808 URL: https://svnweb.freebsd.org/changeset/base/361808
Log: MFC rS361348: DCTCP: update alpha only once after loss recovery. In mixed ECN marking and loss scenarios it was found, that the alpha value of DCTCP is updated two times. The second update happens with freshly initialized counters indicating to ECN loss. Overall this leads to alpha not adjusting as quickly as expected to ECN markings, and therefore lead to excessive loss. Reported by: Cheng Cui Reviewed by: chengc_netapp.com, rrs, tuexen (mentor) Approved by: tuexen (mentor), rgrimes (mentor, blanket) Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D24817 Modified: stable/12/sys/netinet/cc/cc_dctcp.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/netinet/cc/cc_dctcp.c ============================================================================== --- stable/12/sys/netinet/cc/cc_dctcp.c Thu Jun 4 20:48:57 2020 (r361807) +++ stable/12/sys/netinet/cc/cc_dctcp.c Thu Jun 4 21:02:24 2020 (r361808) @@ -154,10 +154,8 @@ dctcp_ack_received(struct cc_var *ccv, uint16_t type) * Update the fraction of marked bytes at the end of * current window size. */ - if ((IN_FASTRECOVERY(CCV(ccv, t_flags)) && - SEQ_GEQ(ccv->curack, CCV(ccv, snd_recover))) || - (!IN_FASTRECOVERY(CCV(ccv, t_flags)) && - SEQ_GT(ccv->curack, dctcp_data->save_sndnxt))) + if (!IN_FASTRECOVERY(CCV(ccv, t_flags)) && + SEQ_GT(ccv->curack, dctcp_data->save_sndnxt)) dctcp_update_alpha(ccv); } else newreno_cc_algo.ack_received(ccv, type); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
