Earlier this year AMD began posting Linux kernel patches for >a href=”https://www.phoronix.com/news/AMD-Zen-4-IBS-Linux”>Instruction Based Sampling (IBS) extensions coming with Zen 4 processors. With Linux 5.19 the Zen 4 IBS extensions landed while now with Linux 6.0 the perf tools have been updated for dealing with Zen 4 IBS.
Sent out on Thursday for the Linux 6.0 merge window were the perf tools changes. Notable among the tooling updates is supporting Zen 4 IBS:
Add support for new AMD IBS (Instruction Based Sampling) features:
With the DataSrc extensions, the source of data can be decoded among:
– Local L3 or other L1/L2 in CCX.
– A peer cache in a near CCX.
– Data returned from DRAM.
– A peer cache in a far CCX.
– DRAM address map with “long latency” bit set.
– Data returned from MMIO/Config/PCI/APIC.
– Extension Memory (S-Link, GenZ, etc – identified by the CS target and/or address map at DF’s choice).
– Peer Agent Memory.
Aside from getting the perf tools ready for Zen 4 Instruction Based Sampling, other tooling updates including a new “perf lock contention” subtool, a “perf kwork” tool to trace time properties of kernel work, support hardware tracing with Intel PT on guest VMs, the Intel Meteor Lake JSON file for perf events has been added, various hybrid system enhancements, and other smaller changes.
Image: AMD
As reported in numerous articles over many months, AMD engineers have been very busy preparing the Zen 4 Linux support for launch-day. It appears they have all their bases covered now aside from some late audio driver code and are now working on some of the other “nice to have” but not mandatory features like around this IBS perf integration. We’ll see soon enough how well AMD Ryzen Zen 4 processors work under Linux.
Source: https://www.phoronix.com/news/Linux-6.0-Zen4-IBS-Perf-Tools
