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, 6 insertions, 6 deletions

diff --git a/src/or/channel.c b/src/or/channel.c
index 7fa9768171..845fc3cb44 100644
--- a/src/or/channel.c
+++ b/src/or/channel.c
@@ -3241,12 +3241,12 @@ channel_timestamp_active(channel_t *chan)
   time_t now = time(NULL);
 
   tor_assert(chan);
-  chan->timestamp_xfer_ms = monotime_coarse_absolute_msec();
+  monotime_coarse_get(&chan->timestamp_xfer);
 
   chan->timestamp_active = now;
 
   /* Clear any potential netflow padding timer. We're active */
-  chan->next_padding_time_ms = 0;
+  monotime_coarse_zero(&chan->next_padding_time);
 }
 
 /**
@@ -3311,13 +3311,13 @@ channel_timestamp_recv(channel_t *chan)
 {
   time_t now = time(NULL);
   tor_assert(chan);
-  chan->timestamp_xfer_ms = monotime_coarse_absolute_msec();
+  monotime_coarse_get(&chan->timestamp_xfer);
 
   chan->timestamp_active = now;
   chan->timestamp_recv = now;
 
   /* Clear any potential netflow padding timer. We're active */
-  chan->next_padding_time_ms = 0;
+  monotime_coarse_zero(&chan->next_padding_time);
 }
 
 /**
@@ -3332,13 +3332,13 @@ channel_timestamp_xmit(channel_t *chan)
   time_t now = time(NULL);
   tor_assert(chan);
 
-  chan->timestamp_xfer_ms = monotime_coarse_absolute_msec();
+  monotime_coarse_get(&chan->timestamp_xfer);
 
   chan->timestamp_active = now;
   chan->timestamp_xmit = now;
 
   /* Clear any potential netflow padding timer. We're active */
-  chan->next_padding_time_ms = 0;
+  monotime_coarse_zero(&chan->next_padding_time);
 }
 
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