Re: [Qemu-devel] [PATCH] Kick io-thread on qemu_chr_accept_input
On 2012-03-16 14:18, Jan Kiszka wrote: On 2012-03-16 14:16, Anthony Liguori wrote: On 03/16/2012 07:25 AM, Jan Kiszka wrote: Once a chr frontend is able to receive input again, we need to inform the io-thread about this fact. Otherwise, main_loop_wait may continue to select without the related backend file descriptor in its set. This can cause high input latencies if only low-rate events arrive otherwise. Signed-off-by: Jan Kiszkajan.kis...@siemens.com I'm not nacking this patch, but please note that this is a band-aid as not all char devices actually use qemu_chr_accept_input(). Then they have to be fixed. :) Could you apply the patch in the meantime? It is not band-aid, but a required base to fix such issues. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
Re: [Qemu-devel] [PATCH] Kick io-thread on qemu_chr_accept_input
On 03/16/2012 07:25 AM, Jan Kiszka wrote:
Once a chr frontend is able to receive input again, we need to inform
the io-thread about this fact. Otherwise, main_loop_wait may continue to
select without the related backend file descriptor in its set. This can
cause high input latencies if only low-rate events arrive otherwise.
Signed-off-by: Jan Kiszkajan.kis...@siemens.com
I'm not nacking this patch, but please note that this is a band-aid as not all
char devices actually use qemu_chr_accept_input().
Regards,
Anthony Liguori
---
/me wonders if a similar issue explains the slirp slowness under KVM
with in-kernel irqchip enabled. Need to check...
qemu-char.c |1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/qemu-char.c b/qemu-char.c
index 9a5be75..a589a84 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -177,6 +177,7 @@ void qemu_chr_accept_input(CharDriverState *s)
{
if (s-chr_accept_input)
s-chr_accept_input(s);
+qemu_notify_event();
}
void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...)
Re: [Qemu-devel] [PATCH] Kick io-thread on qemu_chr_accept_input
On 2012-03-16 14:16, Anthony Liguori wrote: On 03/16/2012 07:25 AM, Jan Kiszka wrote: Once a chr frontend is able to receive input again, we need to inform the io-thread about this fact. Otherwise, main_loop_wait may continue to select without the related backend file descriptor in its set. This can cause high input latencies if only low-rate events arrive otherwise. Signed-off-by: Jan Kiszkajan.kis...@siemens.com I'm not nacking this patch, but please note that this is a band-aid as not all char devices actually use qemu_chr_accept_input(). Then they have to be fixed. :) Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux
