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| Started by | Michael Ellerman <patch-notifications@ellerman.id.au> |
|---|---|
| First post | 2017-06-05 12:30 +0200 |
| Last post | 2017-06-05 13:20 +0200 |
| Articles | 2 — 2 participants |
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Re: [v2] powerpc: handle simultaneous interrupts at once Michael Ellerman <patch-notifications@ellerman.id.au> - 2017-06-05 12:30 +0200
Re: [v2] powerpc: handle simultaneous interrupts at once Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2017-06-05 13:20 +0200
| From | Michael Ellerman <patch-notifications@ellerman.id.au> |
|---|---|
| Date | 2017-06-05 12:30 +0200 |
| Subject | Re: [v2] powerpc: handle simultaneous interrupts at once |
| Message-ID | <tOXqO-1Ey-15@gated-at.bofh.it> |
On Thu, 2017-03-16 at 08:55:45 UTC, Christophe Leroy wrote: > It often happens to have simultaneous interrupts, for instance > when having double Ethernet attachment. With the current > implementation, we suffer the cost of kernel entry/exit for each > interrupt. > > This patch introduces a loop in __do_irq() to handle all interrupts > at once before returning. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/45cb08f4791ce6a15c54598b4cb73d cheers
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| From | Benjamin Herrenschmidt <benh@kernel.crashing.org> |
|---|---|
| Date | 2017-06-05 13:20 +0200 |
| Message-ID | <tOYdb-2bU-1@gated-at.bofh.it> |
| In reply to | #1657487 |
On Mon, 2017-06-05 at 20:21 +1000, Michael Ellerman wrote: > On Thu, 2017-03-16 at 08:55:45 UTC, Christophe Leroy wrote: > > It often happens to have simultaneous interrupts, for instance > > when having double Ethernet attachment. With the current > > implementation, we suffer the cost of kernel entry/exit for each > > interrupt. > > > > This patch introduces a loop in __do_irq() to handle all interrupts > > at once before returning. > > > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > > Applied to powerpc next, thanks. > > https://git.kernel.org/powerpc/c/45cb08f4791ce6a15c54598b4cb73d Hrm, I hadn't noticed that patch... We used to do that and then removed the code for it. There's a cost, sometimes noticeable, to an extra call to ppc_md.get_irq. Why not have your get_irq (or eoi) implementation set a per-cpu requesting a new spin of the loop ? We could move the xive force replay stuff to use the same thing. Ben.
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