Hey all,
I think some form of this is back between 6.12 and 6.15 on our fractious AMD EPYC 7702. The symptom appears to be that the core will not boost past 2 GHz (the nominal frequency), so we lose out on 1.36 GHz of boost frequency. Downgrade from 6.15.7 to LTS (6.12.39) seems to fix it.
Keeping an eye out for other threads reporting similar symptoms on recent kernels:
[ 0.000000] Linux version 6.15.7-xanmod1 (nixbld@localhost) (gcc (GCC) 14.2.1 20250322, GNU ld (GNU Binutils) 2.44) #1-NixOS SMP PREEMPT_DYNAMIC Tue Jan 1 00:00:00 UTC 1980
# cat /proc/cmdline [snip] amd_pstate=active amd_prefcore=enable amd_pstate.shared_mem=1
# cat /proc/cpuinfo [snip] processor : 127 vendor_id : AuthenticAMD cpu family : 23 model : 49 model name : AMD EPYC 7702 64-Core Processor stepping : 0 microcode : 0x830107d cpu MHz : 400.000 cache size : 512 KB physical id : 0 siblings : 128 core id : 63 cpu cores : 64 apicid : 127 initial apicid : 127 fpu : yes fpu_exception : yes cpuid level : 16 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid extd_apicid aperfmperf rapl pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs skinit wdt tce topoext perfctr_core perfctr_nb bpext perfctr_llc mwaitx cpb cat_l3 cdp_l3 hw_pstate ssbd mba ibrs ibpb stibp vmmcall fsgsbase bmi1 avx2 smep bmi2 cqm rdt_a rdseed adx smap clflushopt clwb sha_ni xsaveopt xsavec xgetbv1 xsaves cqm_llc cqm_occup_llc cqm_mbm_total cqm_mbm_local clzero irperf xsaveerptr rdpru wbnoinvd amd_ppin arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold avic v_vmsave_vmload vgif v_spec_ctrl umip rdpid overflow_recov succor smca sev sev_es bugs : sysret_ss_attrs spectre_v1 spectre_v2 spec_store_bypass retbleed smt_rsb srso ibpb_no_ret bogomips : 3992.75 TLB size : 3072 4K pages clflush size : 64 cache_alignment : 64 address sizes : 43 bits physical, 48 bits virtual power management: ts ttp tm hwpstate cpb eff_freq_ro [13] [14]
# cpupower frequency-info analyzing CPU 76: driver: amd-pstate-epp CPUs which run at the same hardware frequency: 76 CPUs which need to have their frequency coordinated by software: 76 energy performance preference: performance hardware limits: 408 MHz - 3.36 GHz available cpufreq governors: performance powersave current policy: frequency should be within 1.51 GHz and 3.36 GHz. The governor "performance" may decide which speed to use within this range. current CPU frequency: 1.98 GHz (asserted by call to kernel) boost state support: Supported: yes Active: yes amd-pstate limits: Highest Performance: 255. Maximum Frequency: 3.36 GHz. Nominal Performance: 152. Nominal Frequency: 2.00 GHz. Lowest Non-linear Performance: 115. Lowest Non-linear Frequency: 1.51 GHz. Lowest Performance: 31. Lowest Frequency: 400 MHz. Preferred Core Support: 0. Preferred Core Ranking: 255.
Regards, Morgan
-----Original Message----- From: Greg Kroah-Hartman gregkh@linuxfoundation.org Sent: Sunday, September 8, 2024 7:30 AM To: Christian Heusel christian@heusel.eu Cc: Mario Limonciello mario.limonciello@amd.com; Jones, Morgan Morgan.Jones@viasat.com; Sasha Levin sashal@kernel.org; linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org; David Arcari darcari@redhat.com; Dhananjay Ugwekar Dhananjay.Ugwekar@amd.com; rafael@kernel.org; viresh.kumar@linaro.org; gautham.shenoy@amd.com; perry.yuan@amd.com; skhan@linuxfoundation.org; li.meng@amd.com; ray.huang@amd.com; stable@vger.kernel.org; Linux kernel regressions list regressions@lists.linux.dev Subject: [EXTERNAL] Re: linux-6.6.y regression on amd-pstate
On Sun, Sep 08, 2024 at 04:12:28PM +0200, Christian Heusel wrote:
Hey Greg,
On 24/09/08 04:05PM, Greg Kroah-Hartman wrote:
On Thu, Sep 05, 2024 at 04:14:26PM -0500, Mario Limonciello wrote:
- stable
- regressions
New subject
Great news.
Greg, Sasha,
Can you please pull in these 3 commits specifically to 6.6.y to fix a regression that was reported by Morgan in 6.6.y:
commit 12753d71e8c5 ("ACPI: CPPC: Add helper to get the highest performance value")
This is fine, but:
commit ed429c686b79 ("cpufreq: amd-pstate: Enable amd-pstate preferred core support")
This is not a valid git id in Linus's tree :(
f3a052391822 ("cpufreq: amd-pstate: Enable amd-pstate preferred core support")
commit 3d291fe47fe1 ("cpufreq: amd-pstate: fix the highest frequency issue which limits performance")
And neither is this :(
bf202e654bfa ("cpufreq: amd-pstate: fix the highest frequency issue which limits performance")
So perhaps you got them wrong?
I have added the ID's of the matching commits from Linus' tree above! :)
Thanks, that works, all now queued up.
greg k-h