web api call performance tuning - asp.net

Question

I am trying to figure find why my api is taking ~5 secs working on 1000 records,is that good or bad?I want to know what tools are there in asp.net webapi to figure out which piece of code or where its consuming time and fine tune the performance
CODE:-
List<LookaheadRunInfo> lookaheadRunsInfo = new List<LookaheadRunInfo>();
List<lookahead_run> lookaheadRunData = new List<lookahead_run>();
if (!filterCriteria.labeled)
{
lookaheadRunData = bitDB.lookahead_run.Where(x => x.lookahead_run_status == null && x.submission_time != null).OrderByDescending(x => x.submission_time).Skip(filterCriteria.PageNumber * filterCriteria.PageSize).Take(filterCriteria.PageSize).ToList();
}
else
{
lookaheadRunData = bitDB.lookahead_run.OrderByDescending(x => x.submission_time).Skip(filterCriteria.PageNumber * filterCriteria.PageSize).Take(filterCriteria.PageSize).ToList();
}
foreach (var lookaheadRunRow in lookaheadRunData)
{
var lookaheadRunInfo = new LookaheadRunInfo();
var lookaheadRunId = lookaheadRunRow.lookahead_run_id;
lookaheadRunInfo.ECJobLink = lookaheadRunRow.ec_job_link;
lookaheadRunInfo.UserSubmitted = lookaheadRunRow.submitted_by;
lookaheadRunInfo.SubmittedTime = lookaheadRunRow.submission_time.ToString();
lookaheadRunInfo.RunStatus = lookaheadRunRow.lookahead_run_status;
var completionTime = lookaheadRunRow.completion_time;
if (completionTime == null)
{
lookaheadRunInfo.ElapsedTime = (DateTime.UtcNow - lookaheadRunRow.submission_time).ToString();
}
else
{
lookaheadRunInfo.ElapsedTime = (lookaheadRunRow.completion_time - lookaheadRunRow.submission_time).ToString();
}
List<String> gerrits = new List<String>();
List<string> lookaheadRunChangeListIds = new List<string>();
if (!filterCriteria.labeled)
{
lookaheadRunChangeListIds = (from lrcl in bitDB.lookahead_run_change_list
join cl in bitDB.change_lists on lrcl.change_list_id equals cl.change_list_id
where lrcl.lookahead_run_id == lookaheadRunId
//and cl.change_list_id not in (select clcl.change_list_id from component_labels_change_lists as clcl)
//where !(from clcl in bitDB.component_labels_change_lists select clcl.change_list_id).Contains(cl.change_list_id)
where !bitDB.component_labels_change_lists.Any(clcl => clcl.change_list_id == cl.change_list_id)
select cl.change_list.ToString()).ToList();
}
else
{
lookaheadRunChangeListIds = (from lrcl in bitDB.lookahead_run_change_list
join cl in bitDB.change_lists on lrcl.change_list_id equals cl.change_list_id
where lrcl.lookahead_run_id == lookaheadRunId
select cl.change_list.ToString()).ToList();
}
//bitDB.Log = Console.Out;
//lookaheadRunInfo.gerrits = gerrits;
lookaheadRunInfo.gerrits = lookaheadRunChangeListIds;
if (lookaheadRunChangeListIds.Count != 0 && filterCriteria.labeled == false)
{
lookaheadRunsInfo.Add(lookaheadRunInfo);
}
else if (filterCriteria.labeled == true)
{
lookaheadRunsInfo.Add(lookaheadRunInfo);
}
}
return lookaheadRunsInfo;