Use monotime_coarse for transfer times and padding times

Using absolute_msec requires a 64-bit division operation every time
we calculate it, which gets expensive on 32-bit architectures.
Instead, just use the lazy "monotime_coarse_get()" operation, and
don't convert to milliseconds until we absolutely must.

In this case, it seemed fine to use a full monotime_coarse_t rather
than a truncated "stamp" as we did to solve this problem for the
timerstamps in buf_t and packed_cell_t: There are vastly more cells
and buffer chunks than there are channels, and using 16 bytes per
channel in the worst case is not a big deal.

There are still more millisecond operations here than strictly
necessary; let's see any divisions show up in profiles.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/test/test_channel.c b/src/test/test_channel.c
index 55d43a04e5..425c93f42f 100644
--- a/src/test/test_channel.c
+++ b/src/test/test_channel.c
@@ -703,7 +703,7 @@ test_channel_inbound_cell(void *arg)
   old_count = test_chan_fixed_cells_recved;
   channel_process_cell(chan, cell);
   tt_int_op(test_chan_fixed_cells_recved, OP_EQ, old_count);
-  tt_u64_op(chan->timestamp_xfer_ms, OP_EQ, 0);
+  tt_assert(monotime_coarse_is_zero(&chan->timestamp_xfer));
   tt_u64_op(chan->timestamp_active, OP_EQ, 0);
   tt_u64_op(chan->timestamp_recv, OP_EQ, 0);
 
@@ -716,10 +716,10 @@ test_channel_inbound_cell(void *arg)
   channel_process_cell(chan, cell);
   tt_int_op(test_chan_fixed_cells_recved, OP_EQ, old_count + 1);
   /* We should have a series of timestamp set. */
-  tt_u64_op(chan->timestamp_xfer_ms, OP_NE, 0);
+  tt_assert(!monotime_coarse_is_zero(&chan->timestamp_xfer));
   tt_u64_op(chan->timestamp_active, OP_NE, 0);
   tt_u64_op(chan->timestamp_recv, OP_NE, 0);
-  tt_u64_op(chan->next_padding_time_ms, OP_EQ, 0);
+  tt_assert(monotime_is_zero(&chan->next_padding_time));
   tt_u64_op(chan->n_cells_recved, OP_EQ, 1);
   tt_u64_op(chan->n_bytes_recved, OP_EQ, get_cell_network_size(0));