Messages in this thread | | | Date | Fri, 22 Mar 2019 11:47:43 -0500 | From | Bjorn Helgaas <> | Subject | Re: [PATCH v3 09/10] NTB: Add MSI interrupt support to ntb_transport |
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Hi Logan,
Drive-by nits:
On Thu, Mar 21, 2019 at 06:06:44PM -0600, Logan Gunthorpe wrote: > Introduce the module parameter 'use_msi' which, when set uses
s/set/set,/
> MSI interrupts instead of doorbells for each queue pair (QP). T > he parameter is only available if NTB MSI support is configured into
Spurious newline in the middle of "The".
> the kernel. We also require there to be more than one memory window > (MW) so that an extra one is available to forward the APIC region. > > To use MSIs, we request one interrupt per QP and forward the MSI address > and data to the peer using scratch pad registers (SPADS) above the MW > spads. (If there are not enough SPADS the MSI interrupt will not be used.)
/spads/SPADS/ for consistency
> Once registered, we simply use ntb_msi_peer_trigger and the recieving
s/recieving/receiving/
> ISR simply queues up the rxc_db_work for the queue. > > This addition can significantly improve performance of ntb_transport. > In a simple, untuned, apples-to-apples comparision using ntb_netdev > and iperf with switchtec hardware, I see 3.88Gb/s without MSI > interrupts and 14.1Gb/s which is a more than 3x improvement.
s/which is/with MSI, which is/
Bjorn
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