Magic-trace – High-resolution traces of what a process is doing
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Re: Magic-trace – High-resolution traces of what a process is doing
#2Hi HN! I'm Clark, one of the maintainers of magic-trace.
magic-trace was submitted before, our first announcement was this blog post: https://blog.janestreet.com/magic-trace/.
Since then, we've worked hard at making magic-trace more accessible to outside users. We've heard stories of people thinking this was cool before but being unable to even find a download link.
I'm posting this here because we just released "version 1.0", which is the first version that we think is sufficiently user-friendly for it to be worth your time to experiment with.
And uhh... sorry in advance if you run into hiccups despite our best efforts. Going from dozens of internal users to anyone and everyone is bound to discover new corners we haven't considered yet. Let us know if you run into trouble!
Re: Magic-trace – High-resolution traces of what a process is doing
#3Needs a Skylake or later CPU, linuxers can
cat /sys/devices/cpu/caps/pmu_name
Re: Magic-trace – High-resolution traces of what a process is doing
#4Needs a Skylake or later CPU, linuxers can cat /sys/devices/cpu/caps/pmu_name to find if they're invited to the party
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/cpuinfo
Re: Magic-trace – High-resolution traces of what a process is doing
#5Hi HN! I'm Clark, one of the maintainers of magic-trace. magic-trace was submitted before, our first announcement was this blog post: https://blog.janestreet.com/magic-trace/ . Since then, we've worked hard at making magic-trace more accessible to outside users. We've heard stories of people thinking this was cool before but being unable to even find a download link. I'm posting this here because we just released "ve…
Thanks for sharing this.
Re: Magic-trace – High-resolution traces of what a process is doing
#6Nice. And it satisfies my curiosity about whether trading firms are switching to AMD or not
Re: Magic-trace – High-resolution traces of what a process is doing
#7Tangentially related. But i really love the podcast from the janestreet people: signals and threads.
Re: Magic-trace – High-resolution traces of what a process is doing
#8Jane Street is a prop trading shop. I heard that they take tech seriously, but still impressed to see them at the front of HN with a tool like this.
Re: Magic-trace – High-resolution traces of what a process is doing
#9Nice. And it satisfies my curiosity about whether trading firms are switching to AMD or not
I don’t know that this definitively answers that question. It’s possible to use a different architecture based on cost/performance and keep a small population of Intel machines in service because you want access to their superior PMUs. Most of what you learn on the latter would still apply to the former.
Re: Magic-trace – High-resolution traces of what a process is doing
#10Looks really cool. I'm sad that I'll never know; Intel + Linux + non-VM excludes literally every computer I have access to. We're all AMD + Windows, and my only access to Intel Linux machines would be a cloud VM.