Date: Wed, 27 Apr 2016 04:51:28 +0000 (UTC) From: Sepherosa Ziehau <sephe@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r298688 - head/sys/dev/hyperv/netvsc Message-ID: <201604270451.u3R4pSa4090960@repo.freebsd.org>
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Author: sephe Date: Wed Apr 27 04:51:28 2016 New Revision: 298688 URL: https://svnweb.freebsd.org/changeset/base/298688 Log: hyperv/hn: Restart sending earlier once we gathered some free TX descs This greatly reduces the oqdrops under heavy workload. For TCP send/recv test (10K concurrent connections): oqdrops is reduced by 17% on sending side, and 57% on receiving side. For nginx-1.8/wrk-4 1KB object test (10K concurrent connections, 4 requests/connection): oqdrops is reduced by 44% on nginx side, and 10% on wrk side. MFC after: 1 week Sponsored by: Microsoft OSTC Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.h head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Modified: head/sys/dev/hyperv/netvsc/hv_net_vsc.h ============================================================================== --- head/sys/dev/hyperv/netvsc/hv_net_vsc.h Wed Apr 27 03:06:53 2016 (r298687) +++ head/sys/dev/hyperv/netvsc/hv_net_vsc.h Wed Apr 27 04:51:28 2016 (r298688) @@ -1185,7 +1185,8 @@ struct hn_tx_ring { #endif int hn_txdesc_cnt; int hn_txdesc_avail; - int hn_has_txeof; + u_short hn_has_txeof; + u_short hn_txdone_cnt; int hn_sched_tx; void (*hn_txeof)(struct hn_tx_ring *); Modified: head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c ============================================================================== --- head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Wed Apr 27 03:06:53 2016 (r298687) +++ head/sys/dev/hyperv/netvsc/hv_netvsc_drv_freebsd.c Wed Apr 27 04:51:28 2016 (r298688) @@ -155,6 +155,8 @@ __FBSDID("$FreeBSD$"); #define HN_DIRECT_TX_SIZE_DEF 128 +#define HN_EARLY_TXEOF_THRESH 8 + struct hn_txdesc { #ifndef HN_USE_TXDESC_BUFRING SLIST_ENTRY(hn_txdesc) link; @@ -793,6 +795,13 @@ hn_txdesc_hold(struct hn_txdesc *txd) atomic_add_int(&txd->refs, 1); } +static __inline void +hn_txeof(struct hn_tx_ring *txr) +{ + txr->hn_has_txeof = 0; + txr->hn_txeof(txr); +} + static void hn_tx_done(struct hv_vmbus_channel *chan, void *xpkt) { @@ -811,6 +820,13 @@ hn_tx_done(struct hv_vmbus_channel *chan txr->hn_has_txeof = 1; hn_txdesc_put(txr, txd); + + ++txr->hn_txdone_cnt; + if (txr->hn_txdone_cnt >= HN_EARLY_TXEOF_THRESH) { + txr->hn_txdone_cnt = 0; + if (txr->hn_oactive) + hn_txeof(txr); + } } void @@ -831,8 +847,8 @@ netvsc_channel_rollup(struct hv_vmbus_ch if (txr == NULL || !txr->hn_has_txeof) return; - txr->hn_has_txeof = 0; - txr->hn_txeof(txr); + txr->hn_txdone_cnt = 0; + hn_txeof(txr); } /*
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