In applications that use little memory and run GC regularly, the cost of
the sweep phase quickly becomes prohibitives as the amount of RAM
increases.
On an ESP32-S3 with 2 MB of external SPIRAM, for example, a trivial GC
cycle takes a minimum of 40ms, virtually all of it in the sweep phase.
Similarly, on the UNIX port with 1 GB of heap, a trivial GC takes 47 ms,
again virtually all of it in the sweep phase.
This commit speeds up the sweep phase in the case most of the heap is empty
by keeping track of the ID of the highest block we allocated in an area
since the last GC.
The performance benchmark run on PYBV10 shows between +0 and +2%
improvement across the existing performance tests. These tests don't
really stress the GC, so they were also run with gc.threshold(30000) and
gc.threshold(10000). For the 30000 case, performance improved by up to
+10% with this commit. For the 10000 case, performance improved by at
least +10% on 6 tests, and up to +25%.
Signed-off-by: Damien George <damien@micropython.org>
Previously sys.path could be modified by append/pop or slice assignment.
This allows `sys.path = [...]`, which can be simpler in many cases, but
also improves CPython compatibility.
It also allows sys.path to be set to a tuple which means that you can
clear sys.path (e.g. temporarily) with no allocations.
This also makes sys.path (and sys.argv for consistency) able to be disabled
via mpconfig. The unix port (and upytesthelper) require them, so they
explicitly verify that they're enabled.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
Otherwise you can get into the confusing state where e.g. sys.ps1 is
enabled in config (via `MICROPY_PY_SYS_PS1_PS2`) but still doesn't actually
get enabled.
Also verify that the required delegation options are enabled in modsys.c.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
NLR buffers are usually quite large (use lots of C stack) and expensive to
push and pop. Some of the time they are only needed to perform clean up if
an exception happens, and then they re-raise the exception.
This commit allows optimizing that scenario by introducing a linked-list of
NLR callbacks that are called automatically when an exception is raised.
They are essentially a light-weight NLR handler that can implement a
"finally" block, i.e. clean-up when an exception is raised, or (by passing
`true` to nlr_pop_jump_callback) when execution leaves the scope.
Signed-off-by: Damien George <damien@micropython.org>
This is intended to be used by the very outer caller of the VM/runtime. It
allows setting a top-level NLR handler that can be jumped to directly, in
order to forcefully abort the VM/runtime.
Enable using:
#define MICROPY_ENABLE_VM_ABORT (1)
Set up the handler at the top level using:
nlr_buf_t nlr;
nlr.ret_val = NULL;
if (nlr_push(&nlr) == 0) {
nlr_set_abort(&nlr);
// call into the VM/runtime
...
nlr_pop();
} else {
if (nlr.ret_val == NULL) {
// handle abort
...
} else {
// handle other exception that propagated to the top level
...
}
}
nlr_set_abort(NULL);
Schedule an abort, eg from an interrupt handler, using:
mp_sched_vm_abort();
Signed-off-by: Damien George <damien@micropython.org>
Use C macros to reduce the size of firmware images when the GC split-heap
feature is disabled.
The code size difference of this commit versus HEAD~2 (ie the commit prior
to MICROPY_GC_SPLIT_HEAP being introduced) when split-heap is disabled is:
bare-arm: +0 +0.000%
minimal x86: +0 +0.000%
unix x64: -16 -0.003%
unix nanbox: -20 -0.004%
stm32: -8 -0.002% PYBV10
cc3200: +0 +0.000%
esp8266: +8 +0.001% GENERIC
esp32: +0 +0.000% GENERIC
nrf: -20 -0.011% pca10040
rp2: +0 +0.000% PICO
samd: -4 -0.003% ADAFRUIT_ITSYBITSY_M4_EXPRESS
The code size difference of this commit versus HEAD~2 split-heap is enabled
with MICROPY_GC_MULTIHEAP=1 (but no extra code to add more heaps):
unix x64: +1032 +0.197% [incl +544(bss)]
esp32: +592 +0.039% GENERIC[incl +16(data) +264(bss)]
This commit adds a new option MICROPY_GC_SPLIT_HEAP (disabled by default)
which, when enabled, allows the GC heap to be split over multiple memory
areas/regions. The first area is added with gc_init() and subsequent areas
can be added with gc_add(). New areas can be added at runtime. Areas are
stored internally as a linked list, and calls to gc_alloc() can be
satisfied from any area.
This feature has the following use-cases (among others):
- The ESP32 has a fragmented OS heap, so to use all (or more) of it the
GC heap must be split.
- Other MCUs may have disjoint RAM regions and are now able to use them
all for the GC heap.
- The user could explicitly increase the size of the GC heap.
- Support a dynamic heap while running on an OS, adding more heap when
necessary.
This uses MP_REGISTER_ROOT_POINTER() to register sched_queue
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register cur_exception,
sys_exitfunc, mp_sys_path_obj, mp_sys_argv_obj and sys_mutable
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register track_reloc_code_list
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register `bluetooth`
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register vfs_cur and
vfs_mount_table instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register lwip_slip_stream
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register dupterm_objs
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
This uses MP_REGISTER_ROOT_POINTER() to register repl_line
instead of using a conditional inside of mp_state_vm_t.
Signed-off-by: David Lechner <david@pybricks.com>
All in-tree uses of MICROPY_PORT_ROOT_POINTERS have been replaced with
MP_REGISTER_ROOT_POINTER(), so now we can remove both
MICROPY_PORT_ROOT_POINTERS and MICROPY_BOARD_ROOT_POINTERS from the code
and remaining config files.
Signed-off-by: David Lechner <david@pybricks.com>
This adds new compile-time infrastructure to parse source code files for
`MP_REGISTER_ROOT_POINTER()` and generates a new `root_pointers.h` header
file containing the collected declarations. This works the same as the
existing `MP_REGISTER_MODULE()` feature.
Signed-off-by: David Lechner <david@pybricks.com>
Prior to this commit, even with unicode disabled .py and .mpy files could
contain unicode characters, eg by entering them directly in a string as
utf-8 encoded.
The only thing the compiler disallowed (with unicode disabled) was using
\uxxxx and \Uxxxxxxxx notation to specify a character within a string with
value >= 0x100; that would give a SyntaxError.
With this change mpy-cross will now accept \u and \U notation to insert a
character with value >= 0x100 into a string (because the -mno-unicode
option is now gone, there's no way to forbid this). The runtime will
happily work with strings with such characters, just like it already works
with strings with characters that were utf-8 encoded directly.
This change simplifies things because there are no longer any feature
flags in .mpy files, and any bytecode .mpy will now run on any target.
Signed-off-by: Damien George <damien@micropython.org>
If MICROPY_SCHEDULER_STATIC_NODES is enabled then C code can declare a
static mp_sched_node_t and schedule a callback using
mp_sched_schedule_node(). In contrast to using mp_sched_schedule(), the
node version will have at most one pending callback outstanding, and will
always be able to schedule if there is nothing already scheduled on this
node. This guarantees that the the callback will be called exactly once
after it is scheduled.
Signed-off-by: Damien George <damien@micropython.org>
This allows the compiler to merge strings: e.g. "update",
"difference_update" and "symmetric_difference_update" will all point to the
same memory.
No functional change.
The size reduction depends on the number of qstrs in the build. The change
this commit brings is:
bare-arm: -4 -0.007%
minimal x86: +150 +0.092% [incl +48(data)]
unix x64: -608 -0.118%
unix nanbox: -572 -0.126% [incl +32(data)]
stm32: -1392 -0.352% PYBV10
cc3200: -448 -0.244%
esp8266: -1208 -0.173% GENERIC
esp32: -1028 -0.068% GENERIC[incl -1020(data)]
nrf: -440 -0.252% pca10040
rp2: -1072 -0.217% PICO
samd: -368 -0.264% ADAFRUIT_ITSYBITSY_M4_EXPRESS
Performance is also improved (on bare metal at least) for the
core_import_mpy_multi.py, core_import_mpy_single.py and core_qstr.py
performance benchmarks.
Originally at adafruit#4583
Signed-off-by: Artyom Skrobov <tyomitch@gmail.com>
The mp_sys_path_obj and mp_sys_argv_obj objects are only used by the
runtime and accessible from Python if MICROPY_PY_SYS is enabled. So
exclude them from the runtime state if this option is disabled.
Signed-off-by: Damien George <damien@micropython.org>
If MICROPY_PY_SYS_PATH_ARGV_DEFAULTS is enabled (which it is by default)
then sys.path and sys.argv will be initialised and populated with default
values. This keeps all bare-metal ports aligned.
Signed-off-by: Damien George <damien@micropython.org>
This commit removes all parts of code associated with the existing
MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE optimisation option, including the
-mcache-lookup-bc option to mpy-cross.
This feature originally provided a significant performance boost for Unix,
but wasn't able to be enabled for MCU targets (due to frozen bytecode), and
added significant extra complexity to generating and distributing .mpy
files.
The equivalent performance gain is now provided by the combination of
MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE (which has
been enabled on the unix port in the previous commit).
It's hard to provide precise performance numbers, but tests have been run
on a wide variety of architectures (x86-64, ARM Cortex, Aarch64, RISC-V,
xtensa) and they all generally agree on the qualitative improvements seen
by the combination of MICROPY_OPT_LOAD_ATTR_FAST_PATH and
MICROPY_OPT_MAP_LOOKUP_CACHE.
For example, on a "quiet" Linux x64 environment (i3-5010U @ 2.10GHz) the
change from CACHE_MAP_LOOKUP_IN_BYTECODE, to LOAD_ATTR_FAST_PATH combined
with MAP_LOOKUP_CACHE is:
diff of scores (higher is better)
N=2000 M=2000 bccache -> attrmapcache diff diff% (error%)
bm_chaos.py 13742.56 -> 13905.67 : +163.11 = +1.187% (+/-3.75%)
bm_fannkuch.py 60.13 -> 61.34 : +1.21 = +2.012% (+/-2.11%)
bm_fft.py 113083.20 -> 114793.68 : +1710.48 = +1.513% (+/-1.57%)
bm_float.py 256552.80 -> 243908.29 : -12644.51 = -4.929% (+/-1.90%)
bm_hexiom.py 521.93 -> 625.41 : +103.48 = +19.826% (+/-0.40%)
bm_nqueens.py 197544.25 -> 217713.12 : +20168.87 = +10.210% (+/-3.01%)
bm_pidigits.py 8072.98 -> 8198.75 : +125.77 = +1.558% (+/-3.22%)
misc_aes.py 17283.45 -> 16480.52 : -802.93 = -4.646% (+/-0.82%)
misc_mandel.py 99083.99 -> 128939.84 : +29855.85 = +30.132% (+/-5.88%)
misc_pystone.py 83860.10 -> 82592.56 : -1267.54 = -1.511% (+/-2.27%)
misc_raytrace.py 21490.40 -> 22227.23 : +736.83 = +3.429% (+/-1.88%)
This shows that the new optimisations are at least as good as the existing
inline-bytecode-caching, and are sometimes much better (because the new
ones apply caching to a wider variety of map lookups).
The new optimisations can also benefit code generated by the native
emitter, because they apply to the runtime rather than the generated code.
The improvement for the native emitter when LOAD_ATTR_FAST_PATH and
MAP_LOOKUP_CACHE are enabled is (same Linux environment as above):
diff of scores (higher is better)
N=2000 M=2000 native -> nat-attrmapcache diff diff% (error%)
bm_chaos.py 14130.62 -> 15464.68 : +1334.06 = +9.441% (+/-7.11%)
bm_fannkuch.py 74.96 -> 76.16 : +1.20 = +1.601% (+/-1.80%)
bm_fft.py 166682.99 -> 168221.86 : +1538.87 = +0.923% (+/-4.20%)
bm_float.py 233415.23 -> 265524.90 : +32109.67 = +13.756% (+/-2.57%)
bm_hexiom.py 628.59 -> 734.17 : +105.58 = +16.796% (+/-1.39%)
bm_nqueens.py 225418.44 -> 232926.45 : +7508.01 = +3.331% (+/-3.10%)
bm_pidigits.py 6322.00 -> 6379.52 : +57.52 = +0.910% (+/-5.62%)
misc_aes.py 20670.10 -> 27223.18 : +6553.08 = +31.703% (+/-1.56%)
misc_mandel.py 138221.11 -> 152014.01 : +13792.90 = +9.979% (+/-2.46%)
misc_pystone.py 85032.14 -> 105681.44 : +20649.30 = +24.284% (+/-2.25%)
misc_raytrace.py 19800.01 -> 23350.73 : +3550.72 = +17.933% (+/-2.79%)
In summary, compared to MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE, the new
MICROPY_OPT_LOAD_ATTR_FAST_PATH and MICROPY_OPT_MAP_LOOKUP_CACHE options:
- are simpler;
- take less code size;
- are faster (generally);
- work with code generated by the native emitter;
- can be used on embedded targets with a small and constant RAM overhead;
- allow the same .mpy bytecode to run on all targets.
See #7680 for further discussion. And see also #7653 for a discussion
about simplifying mpy-cross options.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
The existing inline bytecode caching optimisation, selected by
MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE, reserves an extra byte in the
bytecode after certain opcodes, which at runtime stores a map index of the
likely location of this field when looking up the qstr. This scheme is
incompatible with bytecode-in-ROM, and doesn't work with native generated
code. It also stores bytecode in .mpy files which is of a different format
to when the feature is disabled, making generation of .mpy files more
complex.
This commit provides an alternative optimisation via an approach that adds
a global cache for map offsets, then all mp_map_lookup operations use it.
It's less precise than bytecode caching, but allows the cache to be
independent and external to the bytecode that is executing. It also works
for the native emitter and adds a similar performance boost on top of the
gain already provided by the native emitter.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
The MP_OBJ_STOP_ITERATION optimisation is a shortcut for creating a
StopIteration() exception object, and means that heap memory does not need
to be allocated for the exception (in cases where it can be used). This
commit allows this optimised object to take an optional argument (before,
it could only have no argument).
The commit also adds some new tests to cover corner cases with
StopIteration and generators that previously did not work.
Signed-off-by: Damien George <damien@micropython.org>
This introduces a new macro to get the main thread and uses it to ensure
that asynchronous exceptions such as KeyboardInterrupt (CTRL+C) are only
scheduled on the main thread. This is more deterministic than being
scheduled on a random thread and is more in line with CPython that only
allow signal handlers to run on the main thread.
Fixes issue #7026.
Signed-off-by: David Lechner <david@pybricks.com>
This moves mp_pending_exception from mp_state_vm_t to mp_state_thread_t.
This allows exceptions to be scheduled on a specific thread.
Signed-off-by: David Lechner <david@pybricks.com>
This commit makes gc_lock_depth have one counter per thread, instead of one
global counter. This makes threads properly independent with respect to
the GC, in particular threads can now independently lock the GC for
themselves without locking it for other threads. It also means a given
thread can run a hard IRQ without temporarily locking the GC for all other
threads and potentially making them have MemoryError exceptions at random
locations (this really only occurs on MCUs with multiple cores and no GIL,
eg on the rp2 port).
The commit also removes protection of the GC lock/unlock functions, which
is no longer needed when the counter is per thread (and this also fixes the
cas where a hard IRQ calling gc_lock() may stall waiting for the mutex).
It also puts the check for `gc_lock_depth > 0` outside the GC mutex in
gc_alloc, gc_realloc and gc_free, to potentially prevent a hard IRQ from
waiting on a mutex if it does attempt to allocate heap memory (and putting
the check outside the GC mutex is now safe now that there is a
gc_lock_depth per thread).
Signed-off-by: Damien George <damien@micropython.org>
On ports where normal heap memory can contain executable code (eg ARM-based
ports such as stm32), native code loaded from an .mpy file may be reclaimed
by the GC because there's no reference to the very start of the native
machine code block that is reachable from root pointers (only pointers to
internal parts of the machine code block are reachable, but that doesn't
help the GC find the memory).
This commit fixes this issue by maintaining an explicit list of root
pointers pointing to native code that is loaded from an .mpy file. This
is not needed for all ports so is selectable by the new configuration
option MICROPY_PERSISTENT_CODE_TRACK_RELOC_CODE. It's enabled by default
if a port does not specify any special functions to allocate or commit
executable memory.
A test is included to test that native code loaded from an .mpy file does
not get reclaimed by the GC.
Fixes#6045.
Signed-off-by: Damien George <damien@micropython.org>
When threads and the GIL are enabled, then the qstr mutex is not needed.
The qstr_mutex field is never used in this case because of:
#if MICROPY_PY_THREAD && !MICROPY_PY_THREAD_GIL
#define QSTR_ENTER() mp_thread_mutex_lock(&MP_STATE_VM(qstr_mutex), 1)
#define QSTR_EXIT() mp_thread_mutex_unlock(&MP_STATE_VM(qstr_mutex))
#else
#define QSTR_ENTER()
#define QSTR_EXIT()
#endif
So, we can completely remove qstr_mutex everywhere when MICROPY_PY_THREAD
&& !MICROPY_PY_THREAD_GIL.
When threads and the GIL are enabled, then the GC mutex is not needed. The
gc_mutex field is never used in this case because of:
#if MICROPY_PY_THREAD && !MICROPY_PY_THREAD_GIL
#define GC_ENTER() mp_thread_mutex_lock(&MP_STATE_MEM(gc_mutex), 1)
#define GC_EXIT() mp_thread_mutex_unlock(&MP_STATE_MEM(gc_mutex))
#else
#define GC_ENTER()
#define GC_EXIT()
#endif
So, we can completely remove gc_mutex everywhere when MICROPY_PY_THREAD
&& !MICROPY_PY_THREAD_GIL.
This commit adds support for sys.settrace, allowing to install Python
handlers to trace execution of Python code. The interface follows CPython
as closely as possible. The feature is disabled by default and can be
enabled via MICROPY_PY_SYS_SETTRACE.
mp_compile no longer takes an emit_opt argument, rather this setting is now
provided by the global default_emit_opt variable.
Now, when -X emit=native is passed as a command-line option, the emitter
will be set for all compiled modules (included imports), not just the
top-level script.
In the future there could be a way to also set this variable from a script.
Fixes issue #4267.
This patch implements a new sys.atexit function which registers a function
that is later executed when the main script ends. It is configurable via
MICROPY_PY_SYS_ATEXIT, disabled by default.
This is not compliant with CPython, rather it can be used to implement a
CPython compatible "atexit" module if desired (similar to how
sys.print_exception can be used to implement functionality of the
"traceback" module).
Behaviour was changed from stack to queue in
8977c7eb58, and this updates variable names
to match. Also updates other references (docs, error messages).
A new option MICROPY_GC_STACK_ENTRY_TYPE is added to select a custom type
instead of size_t for the gc_stack array items. This can be beneficial for
small devices, especially those that are low on memory anyway. If a device
has 1MB or less of heap (and 16-byte GC blocks) then this type can be
uint16_t, saving 128 bytes of RAM.
This patch changes dupterm to call the native C stream methods on the
connected stream objects, instead of calling the Python readinto/write
methods. This is much more efficient for native stream objects like UART
and webrepl and doesn't require allocating a special dupterm array.
This change is a minor breaking change from the user's perspective because
dupterm no longer accepts pure user stream objects to duplicate on. But
with the recent addition of uio.IOBase it is possible to still create such
classes just by inheriting from uio.IOBase, for example:
import uio, uos
class MyStream(uio.IOBase):
def write(self, buf):
# existing write implementation
def readinto(self, buf):
# existing readinto implementation
uos.dupterm(MyStream())
This patch moves the start of the root pointer section in mp_state_ctx_t
so that it skips entries that are not pointers and don't need scanning.
Previously, the start of the root pointer section was at the very beginning
of the mp_state_ctx_t struct (which is the beginning of mp_state_thread_t).
This was the original assembler version of the NLR code was hard-coded to
have the nlr_top pointer at the start of this state structure. But now
that the NLR code is partially written in C there is no longer this
restriction on the location of nlr_top (and a comment to this effect has
been removed in this patch).
So now the root pointer section starts part way through the
mp_state_thread_t structure, after the entries which are not root pointers.
This patch also moves the non-pointer entries for MICROPY_ENABLE_SCHEDULER
outside the root pointer section.
Moving non-pointer entries out of the root pointer section helps to make
the GC more precise and should help to prevent some cases of collectable
garbage being kept.
This patch also has a measurable improvement in performance of the
pystone.py benchmark: on unix x86-64 and stm32 there was an improvement of
roughly 0.6% (tested with both gcc 7.3 and gcc 8.1).
Without the compiler enabled the mp_optimise_value is unused, and the
micropython.opt_level() function is not useful, so exclude these from the
build to save RAM and code size.
Damien Tournoud
Jim Mussared
Damien George
Rob Knegjens
Ayke van Laethem
David Lechner
Artyom Skrobov
Damien George
Milan Rossa
Andrew Leech