On Wed, Jul 11, 2018 at 12:43 PM, Greg Kurz <gr...@kaod.org> wrote: > I've been observing a similar delay on ppc64 with fedora28 guests: > > # dmesg | egrep 'scsi| sd ' > [ 1.530946] scsi host0: Virtio SCSI HBA > [ 1.532452] scsi 0:0:0:0: Direct-Access QEMU QEMU HARDDISK 2.5+ > PQ: 0 ANSI: 5 > [ 21.928378] sd 0:0:0:0: Power-on or device reset occurred > [ 21.930012] sd 0:0:0:0: Attached scsi generic sg0 type 0 > [ 21.931554] sd 0:0:0:0: [sda] 83886080 512-byte logical blocks: (42.9 > GB/40.0 GiB) > [ 21.931929] sd 0:0:0:0: [sda] Write Protect is off > [ 21.933110] sd 0:0:0:0: [sda] Mode Sense: 63 00 00 08 > [ 21.934084] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, > doesn't support DPO or FUA > [ 21.943566] sd 0:0:0:0: [sda] Attached SCSI disk > > Kernel version is 4.16.16-300.fc28.ppc64. And I cannot reproduce the > issue with other distros that have an older kernel, eg, ubuntu 18.04 > with kernel 4.15.0-23-generic. > > My first guess is that it might be a kernel-side regression introduced > in 4.16... maybe bisect ?
Interesting. I just tried kernel 4.17.5 from the mainline ppa on Ubuntu 18.04 and now there is a delay. It's only 7.5 seconds but still noticeable. There was previously no delay with the 4.15 kernel. Definitely seems like it could be something introduced in kernel 4.16. Chris
