On Tue, May 26, 2020 at 09:56:30PM +0200, Peter Zijlstra wrote: > On Tue, May 26, 2020 at 02:58:50PM -0400, Qian Cai wrote: > > > I still don't understand why reading all sysfs files on this system > > could increase that much, but here is the lockdep file after > > running sysfs read to see if you could spot anything obviously, > > > > https://cailca.github.io/files/lockdep.txt > > 00000000f011a2a5 OPS: 20 FD: 45 BD: 1 .+.+: kn->active#834 > > is that somewhere near the number of CPUs you have?
834? No. # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 128 On-line CPU(s) list: 0-127 Thread(s) per core: 2 Core(s) per socket: 32 Socket(s): 2 NUMA node(s): 8 Vendor ID: AuthenticAMD CPU family: 23 Model: 1 Model name: AMD EPYC 7601 32-Core Processor Stepping: 2 CPU MHz: 2932.801 CPU max MHz: 2200.0000 CPU min MHz: 1200.0000 BogoMIPS: 4391.87 Virtualization: AMD-V L1d cache: 32K L1i cache: 64K L2 cache: 512K L3 cache: 8192K NUMA node0 CPU(s): 0-7,64-71 NUMA node1 CPU(s): 8-15,72-79 NUMA node2 CPU(s): 16-23,80-87 NUMA node3 CPU(s): 24-31,88-95 NUMA node4 CPU(s): 32-39,96-103 NUMA node5 CPU(s): 40-47,104-111 NUMA node6 CPU(s): 48-55,112-119 NUMA node7 CPU(s): 56-63,120-127 > > Anyway, there's very long "kn->active#..." chains in there, which seems > to suggest some annotation is all sorts of buggered.
