similar to: linux c/s 561

Hi all, I need a periodic timer running at ideally at 125 microseconds and at least 500 microseconds. I''ve just found the VCPUOP_set_periodic_timer, however there is a comment saying "periods less than one millisecond may not be supported". I will be running on an x64 machine. Is this supported? If not, is there any alternate means of generating a fast interrupt? Regards.

Amos Kong <akong at redhat.com> writes: > When I check hwrng attributes in sysfs, cat process always gets > stuck if guest has only 1 vcpu and uses a slow rng backend. > > Currently we check if there is any tasks waiting to be run on > current cpu in rng_dev_read() by need_resched(). But need_resched() > doesn't work because rng_dev_read() is executing in user context.

Amos Kong <akong at redhat.com> writes: > When I check hwrng attributes in sysfs, cat process always gets > stuck if guest has only 1 vcpu and uses a slow rng backend. > > Currently we check if there is any tasks waiting to be run on > current cpu in rng_dev_read() by need_resched(). But need_resched() > doesn't work because rng_dev_read() is executing in user context.

On (Wed) 10 Sep 2014 [17:07:07], Amos Kong wrote: > When I check hwrng attributes in sysfs, cat process always gets > stuck if guest has only 1 vcpu and uses a slow rng backend. > > Currently we check if there is any tasks waiting to be run on > current cpu in rng_dev_read() by need_resched(). But need_resched() > doesn't work because rng_dev_read() is executing in user

On (Wed) 10 Sep 2014 [17:07:07], Amos Kong wrote: > When I check hwrng attributes in sysfs, cat process always gets > stuck if guest has only 1 vcpu and uses a slow rng backend. > > Currently we check if there is any tasks waiting to be run on > current cpu in rng_dev_read() by need_resched(). But need_resched() > doesn't work because rng_dev_read() is executing in user

Hi. I have a Shuttle box with an AMD Athlon XP 2200+ and 1GB of RAM. I''m normally running it with Debian sarge/sid and kernel 2.6.10-1-k7, as built by Debian. I want to use Xen on it. I built a xen0 kernel which is as close to the Debian kernel as I can (no power management, no HPET timers, broken ISA drivers disabled), disabled /lib/tls, and booted with the new kernel. Everything works.

If we read hwrng by long-running dd process, it takes too much cpu time. When we check hwrng attributes from sysfs by cat, it gets stuck. The problem can only be reproduced with non-smp guest with slow backend. This patchset changed hwrng core to always delay 10 jiffies, cat process have chance to execute protected code, the problem is resolved. Thanks. Amos Kong (2): virtio-rng cleanup: move

If we read hwrng by long-running dd process, it takes too much cpu time. When we check hwrng attributes from sysfs by cat, it gets stuck. The problem can only be reproduced with non-smp guest with slow backend. This patchset changed hwrng core to always delay 10 jiffies, cat process have chance to execute protected code, the problem is resolved. Thanks. Amos Kong (2): virtio-rng cleanup: move

Here's couple of patches to improve the softlockup watchdog. The first changes the softlockup timer from using jiffies to sched_clock() as a timebase. Xen and VMI implement sched_clock() as counting unstolen time, so time stolen by the hypervisor won't cause the watchdog to bite. The second adds per-cpu enable flags for the watchdog timer. This allows the timer to be disabled when the

Here's couple of patches to improve the softlockup watchdog. The first changes the softlockup timer from using jiffies to sched_clock() as a timebase. Xen and VMI implement sched_clock() as counting unstolen time, so time stolen by the hypervisor won't cause the watchdog to bite. The second adds per-cpu enable flags for the watchdog timer. This allows the timer to be disabled when the

From: Razya Ladelsky <razya at il.ibm.com> Date: Thu, 31 Jul 2014 09:47:20 +0300 Subject: [PATCH] vhost: Add polling mode When vhost is waiting for buffers from the guest driver (e.g., more packets to send in vhost-net's transmit queue), it normally goes to sleep and waits for the guest to "kick" it. This kick involves a PIO in the guest, and therefore an exit (and possibly

From: Razya Ladelsky <razya at il.ibm.com> Date: Thu, 31 Jul 2014 09:47:20 +0300 Subject: [PATCH] vhost: Add polling mode When vhost is waiting for buffers from the guest driver (e.g., more packets to send in vhost-net's transmit queue), it normally goes to sleep and waits for the guest to "kick" it. This kick involves a PIO in the guest, and therefore an exit (and possibly

Stamp softlockup thread earlier before do_timer, because the latter is the one to actually trigger lock warning for long-time offline. Or else, I obserevd softlockup warning easily at manual vcpu hot-remove/plug, or when suspend cancel into old context. One point here is to cover both stolen and blocked time to compare with offline threshold. vcpu hotplug falls into ''stolen''

The softlockup watchdog is currently a nuisance in a virtual machine, since the whole system could have the CPU stolen from it for a long period of time. While it would be unlikely for a guest domain to be denied timer interrupts for over 10s, it could happen and any softlockup message would be completely spurious. Earlier I proposed that sched_clock() return time in unstolen nanoseconds, which

The softlockup watchdog is currently a nuisance in a virtual machine, since the whole system could have the CPU stolen from it for a long period of time. While it would be unlikely for a guest domain to be denied timer interrupts for over 10s, it could happen and any softlockup message would be completely spurious. Earlier I proposed that sched_clock() return time in unstolen nanoseconds, which

On Fri, Sep 25, 2015 at 6:40 PM, Celelibi via Syslinux <syslinux at zytor.com> wrote: > 2015-09-25 21:27 UTC+02:00, Geert Stappers via Syslinux <syslinux at zytor.com>: >> On Tue, Sep 15, 2015 at 05:22:40AM -0400, Gene Cumm via Syslinux wrote: >>> On Sep 10, 2015 1:32 AM, "celelibi--- via Syslinux" <syslinux at zytor.com> >>> wrote:

Hi Ingo, This series of patches implements a number of improvements to the softlockup watchdog and its users. They are: 1. Make the watchdog ignore stolen time When running under a hypervisor, the kernel may lose an arbitrary amount of time as "stolen time". This may cause the softlockup watchdog to trigger spruiously. Xen and VMI implement sched_clock() as measuring unstolen time,

Hi Ingo, This series of patches implements a number of improvements to the softlockup watchdog and its users. They are: 1. Make the watchdog ignore stolen time When running under a hypervisor, the kernel may lose an arbitrary amount of time as "stolen time". This may cause the softlockup watchdog to trigger spruiously. Xen and VMI implement sched_clock() as measuring unstolen time,

Fixes message_age field update in config BPDUs. Also checks whether the BPDU message age has exceeded bridge max age before transmitting config BPDUs. Signed-off-by: Kishore A K <KishoreAK@myw.ltindia.com> Index: linux-2.6.7/net/bridge/br_stp.c ============================================================= --- linux-2.6.7/net/bridge/br_stp.c.orig 2004-06-17 20:17:27.000000000 +0530 +++

On 2018?03?28? 12:01, haibinzhang(???) wrote: > On 2018?03?27? 19:26, Jason wrote > On 2018?03?27? 17:12, haibinzhang wrote: >>> handle_tx() will delay rx for a long time when busy tx polling udp packets >>> with short length(ie: 1byte udp payload), because setting VHOST_NET_WEIGHT >>> takes into account only sent-bytes but no time. >> Interesting. >>