[go-nuts] Issues accumulating time.Duration

I‘m building a toy key-value store and I’m trying to compute time stats as
I run unit tests. I get rubbish numbers; they are way too high for Put/
Delete operations, but they make sense for Get. I‘ve been trying to figure
this out all night and can’t see clear anymore, I‘d love a second pair of
eyes. I’ve investigated integer overflows, however time.Duration is a int64which I don't think should overflow.

To gather my metrics, I have a channel that received time.Duration objects:

https://github.com/aybabtme/dskvs/blob/proto/concurrency_test.go#L188

Depending on the operation I want to measure, I fill the channel this way
(see ctx.dur):

https://github.com/aybabtme/dskvs/blob/proto/concurrency_test.go#L196

In the case of a Get request (line 211), I get usable numbers:

2013/07/04 07:38:56 Get operations
2013/07/04 07:38:56 N=2048
      total = 0.004893s
      min = 1527ns
      avg = 2389ns
      med = 1919ns
      max = 137159ns
      p50 = 2968ns
      p9 = 6549ns
      p99 = 31446ns
      p999 = 116621ns
      p9999 = 0ns

However for Put and Delete, the number are rubbish (I know they are because
the test doesn't take 145s to run, neither is the smallest Put done in
22ms):

2013/07/04 07:38:56 Put operations
2013/07/04 07:38:56 N=2048
      total = 145.633327s
      min = 21378504ns
      avg = 71110022ns
      med = 70096754ns
      max = 115325380ns
      p50 = 92633901ns
      p9 = 110740221ns
      p99 = 114924456ns
      p999 = 115311230ns
      p9999 = 0ns

I've handrolled my own little stats struct, this is where the numbers come
from:

https://github.com/aybabtme/dskvs/blob/proto/stats.go

Does anybody have an idea as to what's going on?