On 05.03.25 20:43, Andrii Nakryiko wrote:
On Wed, Mar 5, 2025 at 7:22 AM Oleg Nesterov <oleg@xxxxxxxxxx> wrote:
On 03/04, David Hildenbrand wrote:
Currently, uprobe_write_opcode() implements COW-breaking manually, which is
really far from ideal.
To say at least ;)
David, thanks for doing this. I'll try to read 3/3 tomorrow, but I don't
think I can really help. Let me repeat, this code was written many years
ago, I forgot everything, and today my understanding of mm/ is very poor.
But I'll try anyway.
Are there any uprobe tests / benchmarks that are worth running?
All I know about uprobe tests is that bpf people run a lot of tests which
use uprobes.
Andrii, Jiri, what you advise?
We do have a bunch of tests within BPF selftests:
cd tools/testing/selftest/bpf && make -j$(nproc) && sudo ./test_progs -t uprobe
I stumbled over them, but was so far not successful in building them in
my test VM (did not try too hard, though). Will try harder now that I
know that it actually tests uprobe properly :)
I also built an uprobe-stress tool to validate uprobe optimizations I
was doing, this one is the most stand-alone thing to use for testing,
please consider checking that. You can find it at [0], and see also
[1] and [2] where I was helping Peter to build it from sources, so
that might be useful for you as well, if you run into problems with
building. Running something like `sudo ./uprobe-stress -a10 -t5 -m5
-f3` would hammer on this quite a bit.
Thanks, I'll play with that as well.
I'm just about to leave on a short vacation, so won't have time to go
over patches, but I plan to look at them when I'm back next week.
[0] https://github.com/libbpf/libbpf-bootstrap/tree/uprobe-stress
[1] https://lore.kernel.org/linux-trace-kernel/CAEf4BzZ+ygwfk8FKn5AS_Ny=igvGcFzdDLE2FjcvwjCKazEWMA@xxxxxxxxxxxxxx/
[2] https://lore.kernel.org/linux-trace-kernel/CAEf4BzZqKCR-EQz6LTi-YvFY4RnYb_NnQXtwgZCv6aUo7gjkHg@xxxxxxxxxxxxxx
Oleg.
--
Cheers,
David / dhildenb
