Hi, some calls to read(2) or write(2) take almost exactly 0.5 seconds, while most other syscalls are fast as usual. What could be the reason?
I'm running NetBSD 8.0 x86_64 inside VirtualBox 6.1 on a Windows 10 host. Add hard disks in that VM are added via a SCSI controller. One one of the disks I created a file containing random data and read that via cat(1). It looks like this: ~ $ time cat 80mb >/dev/zero real 0m14.521s user 0m0.000s sys 0m14.521s 43.992198659 CALL write(1,0x7e791cd01000,0x4000) 43.992255371 RET write 16384/0x4000 43.992261517 CALL read(3,0x7e791cd01000,0x4000) 44.492970628 RET read 16384/0x4000 44.492981523 CALL write(1,0x7e791cd01000,0x4000) 44.493084051 RET write 16384/0x4000 44.493091315 CALL read(3,0x7e791cd01000,0x4000) 44.493145233 RET read 16384/0x4000 The VM has plenty of free memory, and the VM is otherwise unused. I ran the "benchmark" in /var/shm as well and got mixed results: /var/shm $ time cat 80mb >/dev/zero sys 0m9.607s /var/shm $ time cat 80mb >/dev/zero sys 0m4.705s /var/shm $ time cat 80mb >/dev/zero sys 0m2.427s /var/shm $ time cat 80mb >/dev/zero sys 0m8.669s /var/shm $ time cat 80mb >/dev/zero sys 0m2.376s How can I further research where this artificial delay comes from, and finally fix it? Roland
