[PATCH] kvm tools: Signal only one thread when injecting console interrupts

[PATCH] kvm tools: Signal only one thread when injecting console interrupts

[Sasha Levin]

Send signals only to the thread which handles console injection
instead of the entire process.

This prevents every single thread from having to ignore SIGALRM
and will help scaling when running large amount of VCPU threads.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/kvm.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/tools/kvm/kvm.c b/tools/kvm/kvm.c
index 2c56a79..22871db 100644
--- a/tools/kvm/kvm.c
+++ b/tools/kvm/kvm.c
@@ -28,6 +28,7 @@
 #include <fcntl.h>
 #include <time.h>
 #include <sys/eventfd.h>
+#include <asm/unistd.h>
 
 #define DEFINE_KVM_EXIT_REASON(reason) [reason] = #reason
 
@@ -529,8 +530,9 @@ void kvm__start_timer(struct kvm *kvm)
 
 	memset(&sev, 0, sizeof(struct sigevent));
 	sev.sigev_value.sival_int	= 0;
-	sev.sigev_notify		= SIGEV_SIGNAL;
+	sev.sigev_notify		= SIGEV_THREAD_ID;
 	sev.sigev_signo			= SIGALRM;
+	sev._sigev_un._tid		= syscall(__NR_gettid);
 
 	if (timer_create(CLOCK_REALTIME, &sev, &kvm->timerid) < 0)
 		die("timer_create()");
-- 
1.7.5.3

Re: [PATCH] kvm tools: Signal only one thread when injecting console interrupts

[Asias He]

On 06/16/2011 05:33 AM, Sasha Levin wrote:
> Send signals only to the thread which handles console injection
> instead of the entire process.
> 
> This prevents every single thread from having to ignore SIGALRM
> and will help scaling when running large amount of VCPU threads.
> 
> Suggested-by: Ingo Molnar <mingo@elte.hu>
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>


This one is much simpler than the sig_block patches and also resolves
the getaddrinfo() problem for me in virtio net thread.

Tested-by: Asias He <asias.hejun@gmail.com>

-- 
Best Regards,
Asias He

Re: [PATCH] kvm tools: Signal only one thread when injecting console interrupts

[Ingo Molnar]

* Asias He <asias.hejun@gmail.com> wrote:

> On 06/16/2011 05:33 AM, Sasha Levin wrote:
> > Send signals only to the thread which handles console injection
> > instead of the entire process.
> > 
> > This prevents every single thread from having to ignore SIGALRM
> > and will help scaling when running large amount of VCPU threads.
> > 
> > Suggested-by: Ingo Molnar <mingo@elte.hu>
> > Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> 
> 
> This one is much simpler than the sig_block patches and also resolves
> the getaddrinfo() problem for me in virtio net thread.
> 
> Tested-by: Asias He <asias.hejun@gmail.com>

yep, very nice!

Acked-by: Ingo Molnar <mingo@elte.hu>

Thanks,

	Ingo

Re: [PATCH] kvm tools: Signal only one thread when injecting console interrupts

[Asias He]

On 06/16/2011 03:29 PM, Ingo Molnar wrote:
> * Asias He <asias.hejun@gmail.com> wrote:
> 
>> On 06/16/2011 05:33 AM, Sasha Levin wrote:
>>> Send signals only to the thread which handles console injection
>>> instead of the entire process.
>>>
>>> This prevents every single thread from having to ignore SIGALRM
>>> and will help scaling when running large amount of VCPU threads.
>>>
>>> Suggested-by: Ingo Molnar <mingo@elte.hu>
>>> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
>>
>>
>> This one is much simpler than the sig_block patches and also resolves
>> the getaddrinfo() problem for me in virtio net thread.
>>
>> Tested-by: Asias He <asias.hejun@gmail.com>
> 
> yep, very nice!
> 
> Acked-by: Ingo Molnar <mingo@elte.hu>
> 
> Thanks,
> 
> 	Ingo
> 

Hi, Pekka

Ping. Mind to merge this patch?

-- 
Best Regards,
Asias He