Author: sephe Date: Wed May 18 03:28:51 2016 New Revision: 300105 URL: https://svnweb.freebsd.org/changeset/base/300105
Log: hyperv/vmbus: Use atomic swap and flsl to process event flags Greatly reduce the locked instructions and reduce number of inner loops. MFC after: 1 week Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D6404 Modified: head/sys/dev/hyperv/vmbus/hv_connection.c Modified: head/sys/dev/hyperv/vmbus/hv_connection.c ============================================================================== --- head/sys/dev/hyperv/vmbus/hv_connection.c Wed May 18 03:23:07 2016 (r300104) +++ head/sys/dev/hyperv/vmbus/hv_connection.c Wed May 18 03:28:51 2016 (r300105) @@ -332,32 +332,32 @@ hv_vmbus_on_events(int cpu) */ for (f = 0; f < flag_cnt; f++) { uint32_t rel_id_base; + unsigned long flags; int bit; if (intr_flags[f] == 0) continue; + flags = atomic_swap_long(&intr_flags[f], 0); rel_id_base = f << HV_CHANNEL_ULONG_SHIFT; - for (bit = 0; bit < HV_CHANNEL_ULONG_LEN; bit++) { - if (atomic_testandclear_long(&intr_flags[f], bit)) { - struct hv_vmbus_channel *channel; - uint32_t rel_id; - - rel_id = rel_id_base + bit; - channel = - hv_vmbus_g_connection.channels[rel_id]; - - /* if channel is closed or closing */ - if (channel == NULL || channel->rxq == NULL) - continue; - - if (channel->batched_reading) { - hv_ring_buffer_read_begin( - &channel->inbound); - } - taskqueue_enqueue(channel->rxq, - &channel->channel_task); - } + + while ((bit = ffsl(flags)) != 0) { + struct hv_vmbus_channel *channel; + uint32_t rel_id; + + --bit; /* NOTE: ffsl is 1-based */ + flags &= ~(1UL << bit); + + rel_id = rel_id_base + bit; + channel = hv_vmbus_g_connection.channels[rel_id]; + + /* if channel is closed or closing */ + if (channel == NULL || channel->rxq == NULL) + continue; + + if (channel->batched_reading) + hv_ring_buffer_read_begin(&channel->inbound); + taskqueue_enqueue(channel->rxq, &channel->channel_task); } } } _______________________________________________ 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"
