From: Avi Kivity <avi@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Pekka Enberg <penberg@kernel.org>,
Sasha Levin <levinsasha928@gmail.com>,
john@jfloren.net, kvm@vger.kernel.org, asias.hejun@gmail.com,
gorcunov@gmail.com, prasadjoshi124@gmail.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH 4/6] kvm tools: Add rwlock wrapper
Date: Sat, 28 May 2011 21:14:37 +0300 [thread overview]
Message-ID: <4DE13B8D.90502@redhat.com> (raw)
In-Reply-To: <20110527133128.GA23626@elte.hu>
On 05/27/2011 04:31 PM, Ingo Molnar wrote:
> One furthr optimization would be possible: in case you think we can
> write the signal handler in assembly or build it with gcc flags that
> does not use SSE we might also add a 'lightweight signal handler'
> kind of flag to the kernel, which does not save FPU/vector-CPU(SSE)
> state. In this case signals become *really* fast on x86, almost as
> fast as interrupts.
>
My old fpu rewrite had the potential to do this without a flag. We
simply allocate two fpu contexts per thread (main_fpu and signal_fpu);
when we deliver a signal we clear cr0.ts. If the signal touches the
fpu, we save the fpu state to main_fpu and initialize the fpu; we then
save/restore to signal_fpu until the signal handler exits.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2011-05-28 18:15 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-26 14:25 [PATCH 1/6] kvm tools: Prevent double assignment of guest memory info Sasha Levin
2011-05-26 14:25 ` [PATCH 2/6] kvm tools: Exit VCPU thread only when SIGKVMEXIT is received Sasha Levin
2011-05-26 14:25 ` [PATCH 3/6] kvm tools: Protect IRQ allocations by a mutex Sasha Levin
2011-05-26 14:25 ` [PATCH 4/6] kvm tools: Add rwlock wrapper Sasha Levin
2011-05-26 16:02 ` Pekka Enberg
2011-05-26 16:19 ` Sasha Levin
2011-05-26 18:05 ` Ingo Molnar
2011-05-26 18:11 ` Avi Kivity
2011-05-26 18:21 ` Pekka Enberg
2011-05-26 18:57 ` Sasha Levin
2011-05-26 23:09 ` Mathieu Desnoyers
2011-05-27 10:19 ` Sasha Levin
2011-05-27 10:36 ` Ingo Molnar
2011-05-27 15:52 ` Sasha Levin
2011-05-27 17:10 ` Ingo Molnar
2011-05-27 20:19 ` Sasha Levin
2011-05-28 15:24 ` Ingo Molnar
2011-05-28 16:44 ` Paul E. McKenney
2011-05-28 19:45 ` Sasha Levin
2011-05-29 6:47 ` Avi Kivity
2011-05-29 7:19 ` Ingo Molnar
2011-05-29 15:31 ` Paul E. McKenney
2011-05-29 15:51 ` Paul E. McKenney
2011-05-29 19:54 ` Ingo Molnar
2011-05-30 3:12 ` Paul E. McKenney
2011-05-29 16:22 ` Sasha Levin
2011-05-27 13:14 ` Mathieu Desnoyers
2011-05-29 17:01 ` RCU red-black tree (was: Re: [PATCH 4/6] kvm tools: Add rwlock wrapper) Mathieu Desnoyers
2011-05-29 17:48 ` Sasha Levin
2011-05-30 2:54 ` Mathieu Desnoyers
2011-05-30 6:07 ` Sasha Levin
2011-05-30 11:30 ` Mathieu Desnoyers
2011-05-30 17:38 ` Mathieu Desnoyers
2011-05-30 17:50 ` Mathieu Desnoyers
2011-05-30 17:52 ` Sasha Levin
2011-05-30 18:57 ` Mathieu Desnoyers
2011-05-30 19:11 ` Sasha Levin
2011-05-31 13:05 ` Sasha Levin
2011-05-31 13:09 ` Ingo Molnar
2011-05-31 13:20 ` Sasha Levin
2011-05-31 15:25 ` Ingo Molnar
2011-05-31 19:09 ` Prasad Joshi
2011-05-31 19:31 ` Ingo Molnar
2011-06-02 14:55 ` Mathieu Desnoyers
2011-05-30 3:38 ` Paul E. McKenney
2011-05-30 11:18 ` Mathieu Desnoyers
2011-05-26 20:25 ` [PATCH 4/6] kvm tools: Add rwlock wrapper Ingo Molnar
2011-05-26 23:05 ` Mathieu Desnoyers
2011-05-27 0:58 ` Paul E. McKenney
2011-05-27 9:12 ` Ingo Molnar
2011-05-27 12:48 ` Mathieu Desnoyers
2011-05-27 13:19 ` Ingo Molnar
2011-05-27 13:29 ` Mathieu Desnoyers
2011-05-27 13:36 ` Ingo Molnar
2011-05-27 17:22 ` Paul E. McKenney
2011-05-27 10:25 ` Ingo Molnar
2011-05-27 11:07 ` Ingo Molnar
2011-05-27 11:10 ` Ingo Molnar
2011-05-27 11:24 ` Ingo Molnar
2011-05-27 14:18 ` Mathieu Desnoyers
2011-05-27 14:11 ` Mathieu Desnoyers
2011-05-28 18:12 ` Avi Kivity
2011-05-28 18:32 ` Ingo Molnar
2011-05-29 6:41 ` Avi Kivity
2011-05-29 7:35 ` Ingo Molnar
2011-05-29 7:54 ` Avi Kivity
2011-05-29 12:37 ` Ingo Molnar
2011-05-29 12:48 ` Avi Kivity
2011-05-29 14:27 ` Ingo Molnar
2011-05-29 15:00 ` Avi Kivity
2011-05-29 15:38 ` Paul E. McKenney
2011-05-29 19:33 ` Ingo Molnar
2011-05-30 3:07 ` Paul E. McKenney
2011-05-30 8:12 ` Ingo Molnar
2011-05-27 13:22 ` Mathieu Desnoyers
2011-05-27 13:31 ` Ingo Molnar
2011-05-28 18:14 ` Avi Kivity [this message]
2011-05-27 13:07 ` Ingo Molnar
2011-05-26 14:25 ` [PATCH 5/6] kvm tools: Protect MMIO tree by rwsem Sasha Levin
2011-05-26 14:25 ` [PATCH 6/6] kvm tools: Protect IOPORT " Sasha Levin
2011-05-26 16:01 ` Pekka Enberg
2011-05-26 16:19 ` Sasha Levin
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