tbr1

8 ms·

1.
by tbr1 4y ago
I think this answer has several parts: - I imagine the extra memory bandwidth of newer parts doesn't hurt. The example traces were taken on server-class Ice Lake machines. They just don't overflow for our typical workloads. - We f
2.
by tbr1 4y ago
DDIO operates mostly transparently to software, with the I/O controller feeding DMAs into a slice of L3. Hardware can opt out by setting PCIe TLP header hints, and you have some system-wide configurability via MSRs, but it's not s
3.
by tbr1 4y ago
Absolutely, check out https://github.com/janestreet/magic-trace#privacy-policy and https://github.com/janestreet/magic-trace/wiki/Setting-up-a-... . With a bit of extra configuration, mag
4.
by tbr1 4y ago
Yes, in fact this is how we've been narrowing down performance problems in it and its dependencies :) - https://github.com/let-def/owee/issues/23 - https://github.com/janestreet/magi
5.
by tbr1 4y ago
Absolutely! This is one of the main features of magic-trace, and in fact a primary use-case. You can select a trigger symbol for magic-trace to snapshot upon the next call of. This can be whatever you want, and you can imagine writing code
6.
by tbr1 4y ago
It works best on compiled programs. We do try to support scripted languages with JITs that can emit info about what symbol is located where [1]. Notably, this more or less works for Node.js. It'll work somewhat for Python in that you
7.
by tbr1 4y ago
It's worth noting that aside from the overhead, function call / returns are not quite enough to reconstruct the callstack: tailcalls are just regular branch instructions.
8.
by tbr1 4y ago
We don't have plans to add ARM support largely because we have no in-house expertise with ARM. That said, ARM has CoreSight which sounds like it could support something like magic-trace in some form, and we'd definitely be open to
9.
by tbr1 4y ago
You may also be interested in this wiki page: < https://github.com/janestreet/magic-trace/wiki/Supported-pla... > Intel PT has a bunch of rough edges that we've tried to paper over in magic-trace, bu
10.
by tbr1 4y ago
It's all OCaml, GitHub is just misclassifying it as SML :)
11.
by tbr1 4y ago
We have a bit more color on compatibility in general up on < https://github.com/janestreet/magic-trace/wiki/How-could-mag... > for those interested.
12.
by tbr1 4y ago
One of the maintainers here -- it should work on Broadwell if you're not super keen on the tens-of-nanoseconds timing precision and are okay with microsecond precision (i.e. only want accurate callstacks), grep intel_pt /proc&
13.
by tbr1 5y ago
Small correction: DDIO is not limited to Intel NICs, it's a mostly-transparent-to-the-hardware mechanism by which DMAs are snooped and some fraction of the NIC-local (in the case of multi socket systems) L3 cache is filled with incomin
14.
by tbr1 5y ago
It's quite easy to get it set up once you have a VM with GPU passthrough running (for which there are plenty of guides available online) -- just a double-click installation of a service on the Windows side, compiling a cmake project on
15.
by tbr1 5y ago
Yes, QXL can do that and has built-in support in e.g. virt-manager. It's not going to be fast, but it does work, and is how installation of Looking Glass can be bootstrapped without a physical monitor attached.
16.
Sometimes, the kernel lies about process memory usage(tbrindus.ca)
5 points by tbr1 5y ago|0 comments
17.
by tbr1 6y ago
(Sway dev mentioned in the article here.) To be clear, this loop doesn't exist in Sway proper: it lives in json-c, a third-party library used by a lot more than just Sway. A lockup bug was reported to a lot of projects using json-c a
18.
by tbr1 6y ago
He also wrote "the book" on the subject: https://wayland-book.com/
19.
by tbr1 6y ago
"Wayland forwarding": https://gitlab.freedesktop.org/mstoeckl/waypipe VNC: https://github.com/any1/wayvnc
20.
by tbr1 6y ago
Mir is a Wayland compositor. It may not have started off as one, but is today.
21.
by tbr1 6y ago
Xorg has had a meson build system since 2017: https://gitlab.freedesktop.org/xorg/xserver/-/commit/1549e30... Are you referring to something else?
22.
by tbr1 6y ago
To make the comparison closer to apples-to-apples, the Wayland analog to the Xorg server would be something like GNOME's mutter compositor, which had its first Wayland support out in 2013[1] -- 7 years ago. And the rate of progress has
23.
by tbr1 6y ago
The v4l2 trick "works", but usually the application will use a lossy video codec optimized for faces, not screens. wf-recorder to v4l2 as a poor-man's screenshare to Discord ends in a blurry mess. YMMV with Teams.
24.
by tbr1 6y ago
Developers willing/able to work on X11/Wayland plumbing are a (very) finite number. A single developer can have a large impact. With more of them switching their primary efforts to Wayland, the past few years have seen large impro
25.
by tbr1 6y ago
This comment is mostly correct (as a daily Wayland user), with a few exceptions. > Wayland does almost nothing besides render buffer handling. Input? Applications job. Applications don't do more work to handle input on Wayland as op
26.
by tbr1 6y ago
> ChromeOS runs on Wayland Kind of. The Chrome browser itself doesn't run on Wayland, it runs on a custom compositor (I believe Aura?). Sommelier[1] is a Wayland compositor used for Linux apps on CrOS (Crostini), but Chrome doesn&#x
27.
by tbr1 6y ago
You can write zero-alloc OCaml code, since the standard compiler is very predictable in when it will allocate closures, etc. The Flambda compiler makes things even nicer in removing allocations for some common idioms. [1]: https:/&#x2