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From: Andi Kleen <ak@linux.intel.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: qemu polling KVM_IRQ_LINE_STATUS when stopped
Date: Wed, 18 Oct 2017 10:49:46 -0700	[thread overview]
Message-ID: <20171018174946.GU5109@tassilo.jf.intel.com> (raw)
In-Reply-To: <1ffc9cf7-a81c-6eeb-4823-c6e0ef53d3af@redhat.com>

> Because the polling time is zero here, and fd=7 has POLLIN, it seems
> that QEMU is continuously scheduling a callback (a timer with a deadline
> in the past, or a bottom half).  Can you perhaps attach gdb and see what
> callback it is?

There seem to be multiple.

The ioctl appears to be the PIC timer

  - 6.36% __GI___ioctl                                                                                                                                ▒
           kvm_vm_ioctl                                                                                                                                   ▒
           kvm_set_irq                                                                                                                                    ▒
           kvm_pic_set_irq               

It does something with glib (windows are all closed BTW)

-    2.83%  libglib-2.0.so.0.5200.3   [.] g_main_context_check                                                                                              ▒
   - 2.81% g_main_context_check                                                                                                                             ▒
      - 2.60% main_loop_wait                                                                                                                                ▒
           main                                                                                                                                             ▒
           __libc_start_main                                                                                                                                ▒
           _start                                    

And some AIO is going on, not sure what triggers that.

     1.96% aio_ctx_check                                                                                                                                    ▒

-Andi

  reply	other threads:[~2017-10-18 17:49 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 21:34 qemu polling KVM_IRQ_LINE_STATUS when stopped Andi Kleen
2017-10-18  7:47 ` Paolo Bonzini
2017-10-18 17:49   ` Andi Kleen [this message]
2017-10-18 19:24     ` Paolo Bonzini
2017-10-20  0:34       ` Andi Kleen
2017-10-20  8:32         ` Paolo Bonzini
2017-10-20 14:09           ` Andi Kleen
2017-10-20 15:12             ` Paolo Bonzini
2017-10-20 20:50               ` Andi Kleen
2017-10-20 22:51                 ` Paolo Bonzini
2020-06-25 14:26                   ` Kevin Locke
2020-06-25 16:28                     ` Andi Kleen
2020-06-25 18:41                     ` Paolo Bonzini
2020-06-25 18:56                       ` Kevin Locke
2020-06-25 19:17                         ` Paolo Bonzini
2020-06-25 20:10                           ` Kevin Locke
2020-06-26 15:14                       ` Kevin Locke

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