GCC12 catches various issues in tests at compile time that we want to
catch at runtime. Also glibc 2.34 deprecated various mallinfo related
functions. Add the relevant -Wno-foobar flags to those tests. In one
case, unit_oset.c, the warning was correct and the uninitialized
variable was explicitly set.
Various tests do things which we want to detect at runtime, like
ignoring the result of malloc or doing a deliberate impossibly large
allocation or operations that would result in overflowing or
truncated strings, that generate a warning from gcc.
In once case, mq_setattr called with new and old attrs overlapping,
this was explicitly fixed, in others -Wno-foobar was added to silence
the warning. This is safe even for older gcc, since a compiler will
ignore any -Wno-foobar they don't know about - since they do know they
won't warn for foobar.
cachegrind callgrind dhat exp-bbv gdbserver_tests massif none mpi shared
Mostly these are just updates (and new testcases) under new/tests
The other directories have just #ifdef changes
If you do `malloc(100)` followed by `realloc(200)`, DHAT now adds 100
bytes to the read and write counts for the implicit `memcpy`. This gives
more reasonable results.
I have long been surprised by low writes-per-byte values of around 0.35
for vectors that are grown by doubling. Counting the implicit `memcpy`
increases those numbers to well above 0.5, which is what you'd expect.
The commit also adds a section to the DHAT docs about `realloc`, because
there is some non-obvious behaviour, some of which confused me just a
couple of days ago.
The aim is to make it zero-effort for users to view the profile after
a run. The printed message is as follows:
To view the resulting profile, open
file:///path/to/valgrind/installation/lib/valgrind/dh_view.html
in a web browser, click on "Load..." and then select the file
/path/to/dhat.out.12345
Scroll to the end the displayed page to see a short
explanation of some of the abbreviations used in the page.
This patch adds printing of the message, then filters it out in
dhat/tests/filter_stderr, and updates the .stderr.exp files to
remove blank lines.
This commit thoroughly overhauls DHAT, moving it out of the
"experimental" ghetto. It makes moderate changes to DHAT itself,
including dumping profiling data to a JSON format output file. It also
implements a new data viewer (as a web app, in dhat/dh_view.html).
The main benefits over the old DHAT are as follows.
- The separation of data collection and presentation means you can run a
program once under DHAT and then sort the data in various ways. Also,
full data is in the output file, and the viewer chooses what to omit.
- The data can be sorted in more ways than previously. Some of these
sorts involve useful filters such as "short-lived" and "zero reads or
zero writes".
- The tree structure view avoids the need to choose stack trace depth.
This avoids both the problem of not enough depth (when records that
should be distinct are combined, and may not contain enough
information to be actionable) and the problem of too much depth (when
records that should be combined are separated, making them seem less
important than they really are).
- Byte and block measures are shown with a percentage relative to the
global count, which helps gauge relative significance of different
parts of the profile.
- Byte and blocks measures are also shown with an allocation rate
(bytes and blocks per million instructions), which enables comparisons
across multiple profiles, even if those profiles represent different
workloads.
- Both global and per-node measurements are taken at the global heap
peak ("At t-gmax"), which gives Massif-like insight into the point of
peak memory use.
- The final/liftimes stats are a bit more useful than the old deaths
stats. (E.g. the old deaths stats didn't take into account lifetimes
of unfreed blocks.)
- The handling of realloc() has changed. The sequence `p = malloc(100);
realloc(p, 200);` now increases the total block count by 2 and the
total byte count by 300. Previously it increased them by 1 and 200.
The new handling is a more operational view that better reflects the
effect of allocations on performance. It makes a significant
difference in the results, giving paths involving reallocation (e.g.
repeated pushing to a growing vector) more prominence.
Other things of note:
- There is now testing, both regression tests that run within the
standard test suite, and viewer-specific tests that cannot run within
the standard test suite. The latter are run by loading
dh_view.html?test=1 in a web browser.
- The commit puts all tool lists in Makefiles (and similar files) in the
following consistent order: memcheck, cachegrind, callgrind, helgrind,
drd, massif, dhat, lackey, none; exp-sgcheck, exp-bbv.
- A lot of fields in dh_main.c have been given more descriptive names.
Those names now match those used in dh_view.js.
