This way, we can change the constant in one place. Note that this
requires the use of nested format strings, which is slightly ugly but
safe to do in this instance.
This constant is currently 3 but can be changed easily or integrated
into a user setting. Note that the results are not ideal because during
pretty-printing we're not using any nice rounding rules, so many
percentage values will actually appear as 0.399999 even though they were
rounded to three digits.
This commit adds "Filesystem Events" View to the Profiler. This tab
will present combined information for recorded Filesystem events.
Currently only accumulated count and duration is presented.
Duration amount currently only shows events that took over 1ms,
which means that in most cases 0 is show.
This adds a new view mode to profiler which displays source lines and
samples that occured at those lines. This view can be opened via the
menu or by pressing CTRL-S.
It does this by mapping file names from DWARF to "/usr/src/serenity/..."
i.e. source code should be copied to /usr/src/serenity/Userland and
/usr/src/serenity/Kernel to be visible in this mode.
Currently *all* files contributing to the selected function are loaded
completely which could be a lot of data when dealing with lots of
inlined code.
No need to copy and move them around, just to pass them as a
`String const&` to the constructor.
We still end up copying it to a normal String in the end though...
Also add slightly richer parse errors now that we can include a string
literal with returned errors.
This will allow us to use TRY() when working with JSON data.
This changes browsing through disassembled functions in Profiler from a
painfully sluggish experience into quite a swift one. It's especially
true for profiling the kernel, as it has more than 10 megabytes of DWARF
data to churn through.
/boot/Kernel.debug only contains the symbol table and DWARF debug
information, and has its `.text` and other PT_LOAD segments stripped
out. When we try to parse its data as instructions, we get a crash from
within LibX86.
We now load the actual /boot/Kernel binary when we want to disassemble
kernel functions.
There is no point in keeping around a separate MappedFile object for
/boot/Kernel.debug for each DisassemblyModel we create and re-parsing
the kernel image multiple times. This will significantly speed up
browsing through profile entries from the kernel in disassembly view.
Previously, we assumed that the `.text` segment was loaded at vaddr 0 in
shared object, which is not the case with `-z separate-code` enabled.
Because we didn't do the right calculations to translate an address from
a performance event into its value within the ELF file, Profiler would
try to disassemble out-of-bounds memory locations, leading to a crash.
This commit also changes `LibraryMetadata` to apply to a loaded library
as a whole, not just to one of its segments (like .text or .data). This
lets us simplify the interface, as we no longer have to worry about
`text_base`.
Fixes#10628
Since our executables are position-independent, the address values
extraced from processes don't correspond to their values within the ELF
file. We have to offset the absolute addresses by the load base address
to get the relative symbol that we need for disassembly.
Now that the kernel is compiled as a PIE, all addresses are relative to
the loaded base address, so Symbolication::kernel_base has to be
subtracted off from the absolute addresses if we want to symbolicate
them.
Previously we assumed there were less kernel samples than user samples,
by implicitly using the kernel histogram size for indicies to the user
histogram. Such a profile can be reproduced by profiling a very short
lived program like true: `profile -c true`
Beforehand we were dividing the frame width by the profile length in ms
and then dividing the frame width by the result once more, which is
equivalent to (but slower) just using the length in ms directly, aside
from the case in which the profile is less than 1 ms long, in which
case this would trigger undefined behaviour due to the division by zero
