If you have access to some web area with CGI support, the easiest way to
navigate igprof reports is to use the igprof-navigator script. Have a look
here to see how to set it up.
Depending on whether we are doing performance profiling or memory profiling, the numbers reported represent seconds or the bytes of memory being allocated.
The entry page for the report is a flat list with the cumulative cost of the listed functions and methods. See here for an example.
By clicking of the “Sort by self cost” link you’ll be able to sort the same profile having the most costy functions and methods on top, without considering their children. This is called the “Self cost view”.
All the entries in those two lists are links to their detailed view. For example have a look at the detailed view for fastjet::ClusterSequence::_minheap_faster_tiled_N2_cluster().
Each detailed view describes the statistics for one function, the primary function (in light orange-ish), surrounded by secondary functions. Above the primary function are the callers (in dark green): the functions that called the primary function. Below the primary function are the callees (in light green): the functions the primary function called.
In the first column the number in the brackets indicates the function’s index in the cumulative view. The smaller the index is, the higher the function was in cpu time usage, memory usage or leakage.
The other columns have slightly different meaning depending if you are looking at the callers, the callees or the primary function.
For the primary function the “% total” column is the percentage of the total time spent in the given function and its callees. For the callers and the callees it is the percentage of total time spent calling (or being called by) the primary function. The “Counts” column contains the time spent in the function itself (first sub-column) and the time spent in its children. The “Paths” column is contains the number of different callstack the primary function is found.
For the callers the “% total” column is the percentage of the total time a caller spends in calling the primary function. The “Counts” column shows the number of seconds spent in the function when calling the primary function (first sub-column) and the total cumulative number of seconds spent in the caller or any of its children (second column). The “Paths” column contains similarly the number of callpaths which result in calling the primary function, and the total number of paths a caller function appears on.
For the callees the “% total” column is the percentage of the total time a callee uses when being called by the primary function. The “Counts” column shows the number of seconds spent in the callee when being called by the primary function (first sub-column) and the number of seconds spent in the callee (or its children) in total. The “Paths” column contains similarly the number of callpaths in which the primary function ends up calling the given callee and the number of paths in general a callee appears on.
Symbol name is obviously the mnemonic name associated with a given function.