Date: Wed, 02 Jun 2021 11:57:27 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 256375] iflib/if_em: unplugging network cable causes huge KTorrent slowdown Message-ID: <bug-256375-7501@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D256375 Bug ID: 256375 Summary: iflib/if_em: unplugging network cable causes huge KTorrent slowdown Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Keywords: iflib, performance Severity: Affects Only Me Priority: --- Component: kern Assignee: net@FreeBSD.org Reporter: danfe@FreeBSD.org Created attachment 225494 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D225494&action= =3Dedit procstat -kk output I'm experiencing strange and very prominent performance loss with KTorrent = when unplugging Ethernet cable from em0, that is, switch to WiFi: it now takes several tens seconds for it to update the window contents, react to mouse clicks, and transfer speeds drop down to single bytes per second. At this time, the ktorrent process, as displayed by top(1), is in "iflib" state whi= ch occasionally briefly changes to "e1000_". But once I plug the network cable back, everything goes back to normal, and= the process returns to "select" state like it should. This happens on Lenovo L= 470 laptop with the following NIC: em0@pci0:0:31:6: class=3D0x020000 rev=3D0x21 hdr=3D0x00 vendor=3D0x8= 086 device=3D0x15d8 subvendor=3D0x17aa subdevice=3D0x505f vendor =3D 'Intel Corporation' device =3D 'Ethernet Connection (4) I219-V' class =3D network subclass =3D ethernet Both today's kernel and my normal Jan/Feb'ish kernel behave identically. T= he driver from `net/intel-em-kmod' port does not exhibit this problem. I'm attaching procstat -kk $ktorrent_pid output, in case it could be useful. T= his line looks suspicious as if something is holding the lock: mi_switch+0xc1 _sx_xlock_hard+0x3d1 iflib_media_status+0xf2 ifmedia_ioctl+0= x16a ifhwioctl+0x2bd ifioctl+0x48d kern_ioctl+0x23b sys_ioctl+0xf6 amd64_syscall+0x100 fast_syscall_common+0xf8 Please advise on any other debug information I could provide which may help= to track the bug down and fix it. --=20 You are receiving this mail because: You are the assignee for the bug.=
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