Time slowed down using `S.D.Stopwatch` on Azure

I just ran some code which reports its performance on an Azure Web Sites instance; the result seemed a little off. I re-ran the operation, and indeed it seems consistent: System.Diagnostics.Stopwatch sees an execution time of 12 seconds for an operation that actually took more than three minutes (at least 3m16s).

Debug.WriteLine("Loading dataset in database ...");
var stopwatch = new Stopwatch();
stopwatch.Start();
ProcessDataset(CurrentDataSource.Database.Connection as SqlConnection, parser);
stopwatch.Stop();
Debug.WriteLine("Dataset loaded in database ({0}s)", stopwatch.Elapsed.Seconds);
return (short)stopwatch.Elapsed.Seconds;

This process runs in the context of a WCF Data Service "action" and seeds test data in a SQL Database (this is not production code). Specifically, it:

1. Opens a connection to an Azure SQL Database,
2. Disables a null constraint,
3. Uses System.Data.SqlClient.SqlBulkCopy to lock an empty table and load it using a buffered stream that retrieves a dataset (2.4MB) from Azure Blob Storage via the filesystem, decompresses it (GZip, 4.9MB inflated) and parses it (CSV, 349996 records, parsed with a custom IDataReader using TextFieldParser),
4. Updates a column of the same table to set a common value,
5. Re-enables the null constraint.

No less, no more; there's nothing particularly intensive going on, I figure the operation is mostly network-bound.

Any idea why time is slowing down?

Notes:

• Interestingly, timeouts for both the bulk insert and the update commands had to be increased (set to five minutes). I read that the default is 30 seconds, which is more than the reported 12 seconds; hence, I conclude that SqlClient measures time differently.
• Reports from local execution seem perfectly correct, although it's consistently faster (4-6s using LocalDB) so it may just be that the effects are not noticeable.

You used stopwatch.Elapsed.Seconds to get total time but it is wrong. Elapsed.Seconds is the seconds component of the time interval represented by the TimeSpan structure. Please try stopwatch.Elapsed.TotalSeconds instead.