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From: David Xu <davidxu06@gmail.com>
To: kvm <kvm@vger.kernel.org>
Cc: mst@redhat.com
Subject: reduce networking latency
Date: Wed, 24 Sep 2014 14:40:53 -0400	[thread overview]
Message-ID: <CAGjowiQjF0HKkevZDCVAiOc9-nEQpxkQ+uiY2jkbiiU8n1PusQ@mail.gmail.com> (raw)

Hi Michael,

I found this interesting project from KVM TODO website:

allow handling short packets from softirq or VCPU context
 Plan:
   We are going through the scheduler 3 times
   (could be up to 5 if softirqd is involved)
   Consider RX: host irq -> io thread -> VCPU thread ->
   guest irq -> guest thread.
   This adds a lot of latency.
   We can cut it by some 1.5x if we do a bit of work
   either in the VCPU or softirq context.
 Testing: netperf TCP RR - should be improved drastically
          netperf TCP STREAM guest to host - no regression

Would you mind saying more about the work either in the vCPU or
softirq context? Why it is only for short packets handling? Thanks a
lot!


Regards,

Cong

             reply	other threads:[~2014-09-24 18:40 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-24 18:40 David Xu [this message]
2014-09-29  9:04 ` reduce networking latency Michael S. Tsirkin
2014-10-15 18:30   ` David Xu
2014-10-22 20:35     ` David Xu
2014-10-23  4:15       ` Michael S. Tsirkin
  -- strict thread matches above, loose matches on Subject: below --
2014-06-10 15:29 David Xu

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