Re: [Qemu-devel] fixing qemu busy wait
Il 18/04/2013 20:47, Orr Dvory ha scritto:
is this better?
Yes -- but I don't remember if this was fixed elsewhere. Can you
reproduce the problem in 1.5.0? If so, please send the patch according
to the guidelines at http://wiki.qemu.org/Contribute/SubmitAPatch.
Paolo
diff -uprN qemu-1.4.1/gdbstub.c qemu-1.4.1-fix/gdbstub.c
--- qemu-1.4.1/gdbstub.c2013-04-15 23:25:18.0 +0300
+++ qemu-1.4.1-fix/gdbstub.c2013-04-18 21:35:00.0 +0300
@@ -379,17 +379,22 @@ static void put_buffer(GDBState *s, cons
{
#ifdef CONFIG_USER_ONLY
int ret;
-
+int fd_flags = fcntl (s-fd, F_GETFL, 0);
+fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
while (len 0) {
ret = send(s-fd, buf, len, 0);
if (ret 0) {
if (errno != EINTR errno != EAGAIN)
+{
+fcntl (s-fd, F_SETFL, fd_flags);
return;
+}
} else {
buf += ret;
len -= ret;
}
}
+fcntl (s-fd, F_SETFL, fd_flags);
#else
qemu_chr_fe_write(s-chr, buf, len);
#endif
@@ -2775,6 +2780,7 @@ gdb_handlesig (CPUArchState *env, int si
GDBState *s;
char buf[256];
int n;
+ int fd_flags;
s = gdbserver_state;
if (gdbserver_fd 0 || s-fd 0)
@@ -2793,7 +2799,8 @@ gdb_handlesig (CPUArchState *env, int si
connection. */
if (s-fd 0)
return sig;
-
+ fd_flags = fcntl (s-fd, F_GETFL, 0);
+ fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
sig = 0;
s-state = RS_IDLE;
s-running_state = 0;
@@ -2810,9 +2817,11 @@ gdb_handlesig (CPUArchState *env, int si
{
/* XXX: Connection closed. Should probably wait for another
connection before continuing. */
+ fcntl (s-fd, F_SETFL, fd_flags);
return sig;
}
}
+ fcntl (s-fd, F_SETFL, fd_flags);
sig = s-signal;
s-signal = 0;
return sig;
On Thu, Apr 18, 2013 at 9:46 PM, Orr Dvory gid...@gmail.com
mailto:gid...@gmail.com wrote:
is this better?
diff -uprN qemu-1.4.1/gdbstub.c qemu-1.4.1-fix/gdbstub.c
--- qemu-1.4.1/gdbstub.c2013-04-15 23:25:18.0 +0300
+++ qemu-1.4.1-fix/gdbstub.c2013-04-18 21:35:00.0 +0300
@@ -379,17 +379,22 @@ static void put_buffer(GDBState *s, cons
{
#ifdef CONFIG_USER_ONLY
int ret;
-
+int fd_flags = fcntl (s-fd, F_GETFL, 0);
+fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
while (len 0) {
ret = send(s-fd, buf, len, 0);
if (ret 0) {
if (errno != EINTR errno != EAGAIN)
+{
+fcntl (s-fd, F_SETFL, fd_flags);
return;
+}
} else {
buf += ret;
len -= ret;
}
}
+fcntl (s-fd, F_SETFL, fd_flags);
#else
qemu_chr_fe_write(s-chr, buf, len);
#endif
@@ -2775,6 +2780,7 @@ gdb_handlesig (CPUArchState *env, int si
GDBState *s;
char buf[256];
int n;
+ int fd_flags;
s = gdbserver_state;
if (gdbserver_fd 0 || s-fd 0)
@@ -2793,7 +2799,8 @@ gdb_handlesig (CPUArchState *env, int si
connection. */
if (s-fd 0)
return sig;
-
+ fd_flags = fcntl (s-fd, F_GETFL, 0);
+ fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
sig = 0;
s-state = RS_IDLE;
s-running_state = 0;
@@ -2810,9 +2817,11 @@ gdb_handlesig (CPUArchState *env, int si
{
/* XXX: Connection closed. Should probably wait for another
connection before continuing. */
+ fcntl (s-fd, F_SETFL, fd_flags);
return sig;
}
}
+ fcntl (s-fd, F_SETFL, fd_flags);
sig = s-signal;
s-signal = 0;
return sig;
On Wed, Feb 20, 2013 at 10:38 PM, Paolo Bonzini pbonz...@redhat.com
mailto:pbonz...@redhat.com wrote:
Il 20/02/2013 20:39, Orr Dvory ha scritto:
if (errno != EINTR errno != EAGAIN)
+/* there's no need to restore the
+O_NONBLOCK option. */
return;
+
But it's cleaner to do it anyway. :)
Paolo
Re: [Qemu-devel] fixing qemu busy wait
is this better?
diff -uprN qemu-1.4.1/gdbstub.c qemu-1.4.1-fix/gdbstub.c
--- qemu-1.4.1/gdbstub.c2013-04-15 23:25:18.0 +0300
+++ qemu-1.4.1-fix/gdbstub.c2013-04-18 21:35:00.0 +0300
@@ -379,17 +379,22 @@ static void put_buffer(GDBState *s, cons
{
#ifdef CONFIG_USER_ONLY
int ret;
-
+int fd_flags = fcntl (s-fd, F_GETFL, 0);
+fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
while (len 0) {
ret = send(s-fd, buf, len, 0);
if (ret 0) {
if (errno != EINTR errno != EAGAIN)
+{
+fcntl (s-fd, F_SETFL, fd_flags);
return;
+}
} else {
buf += ret;
len -= ret;
}
}
+fcntl (s-fd, F_SETFL, fd_flags);
#else
qemu_chr_fe_write(s-chr, buf, len);
#endif
@@ -2775,6 +2780,7 @@ gdb_handlesig (CPUArchState *env, int si
GDBState *s;
char buf[256];
int n;
+ int fd_flags;
s = gdbserver_state;
if (gdbserver_fd 0 || s-fd 0)
@@ -2793,7 +2799,8 @@ gdb_handlesig (CPUArchState *env, int si
connection. */
if (s-fd 0)
return sig;
-
+ fd_flags = fcntl (s-fd, F_GETFL, 0);
+ fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
sig = 0;
s-state = RS_IDLE;
s-running_state = 0;
@@ -2810,9 +2817,11 @@ gdb_handlesig (CPUArchState *env, int si
{
/* XXX: Connection closed. Should probably wait for another
connection before continuing. */
+ fcntl (s-fd, F_SETFL, fd_flags);
return sig;
}
}
+ fcntl (s-fd, F_SETFL, fd_flags);
sig = s-signal;
s-signal = 0;
return sig;
On Thu, Apr 18, 2013 at 9:46 PM, Orr Dvory gid...@gmail.com wrote:
is this better?
diff -uprN qemu-1.4.1/gdbstub.c qemu-1.4.1-fix/gdbstub.c
--- qemu-1.4.1/gdbstub.c2013-04-15 23:25:18.0 +0300
+++ qemu-1.4.1-fix/gdbstub.c2013-04-18 21:35:00.0 +0300
@@ -379,17 +379,22 @@ static void put_buffer(GDBState *s, cons
{
#ifdef CONFIG_USER_ONLY
int ret;
-
+int fd_flags = fcntl (s-fd, F_GETFL, 0);
+fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
while (len 0) {
ret = send(s-fd, buf, len, 0);
if (ret 0) {
if (errno != EINTR errno != EAGAIN)
+{
+fcntl (s-fd, F_SETFL, fd_flags);
return;
+}
} else {
buf += ret;
len -= ret;
}
}
+fcntl (s-fd, F_SETFL, fd_flags);
#else
qemu_chr_fe_write(s-chr, buf, len);
#endif
@@ -2775,6 +2780,7 @@ gdb_handlesig (CPUArchState *env, int si
GDBState *s;
char buf[256];
int n;
+ int fd_flags;
s = gdbserver_state;
if (gdbserver_fd 0 || s-fd 0)
@@ -2793,7 +2799,8 @@ gdb_handlesig (CPUArchState *env, int si
connection. */
if (s-fd 0)
return sig;
-
+ fd_flags = fcntl (s-fd, F_GETFL, 0);
+ fcntl (s-fd, F_SETFL, fd_flags ~O_NONBLOCK);
sig = 0;
s-state = RS_IDLE;
s-running_state = 0;
@@ -2810,9 +2817,11 @@ gdb_handlesig (CPUArchState *env, int si
{
/* XXX: Connection closed. Should probably wait for another
connection before continuing. */
+ fcntl (s-fd, F_SETFL, fd_flags);
return sig;
}
}
+ fcntl (s-fd, F_SETFL, fd_flags);
sig = s-signal;
s-signal = 0;
return sig;
On Wed, Feb 20, 2013 at 10:38 PM, Paolo Bonzini pbonz...@redhat.comwrote:
Il 20/02/2013 20:39, Orr Dvory ha scritto:
if (errno != EINTR errno != EAGAIN)
+/* there's no need to restore the
+O_NONBLOCK option. */
return;
+
But it's cleaner to do it anyway. :)
Paolo
Re: [Qemu-devel] fixing qemu busy wait
the new patch is attached... On Sun, Feb 17, 2013 at 6:32 PM, Orr Dvory gid...@gmail.com wrote: Yes it would :) Should I do that? or that you already fixed the issue? On Sun, Feb 17, 2013 at 12:06 AM, Richard Henderson r...@twiddle.netwrote: On 2013-02-15 03:12, Orr Dvory wrote: when debugging with qemu(user mode), qemu waits in infinite loop to read a signal from gdb (when it waits on breakpoint for example). I added sleeps to reduce the cpu usage from 100% to about ~0%. Wouldn't it be better to toggle the O_NONBLOCK state of the file descriptor across this loop? r~ qemu-busy-wait.patch Description: Binary data
Re: [Qemu-devel] fixing qemu busy wait
Am 20.02.2013 20:39, schrieb Orr Dvory: the new patch is attached... Please see http://wiki.qemu.org/Contribute/SubmitAPatch for multiple reasons why your patch won't get applied or get much review as is. Andreas On Sun, Feb 17, 2013 at 6:32 PM, Orr Dvory gid...@gmail.com mailto:gid...@gmail.com wrote: Yes it would :) Should I do that? or that you already fixed the issue? On Sun, Feb 17, 2013 at 12:06 AM, Richard Henderson r...@twiddle.net mailto:r...@twiddle.net wrote: On 2013-02-15 03:12, Orr Dvory wrote: when debugging with qemu(user mode), qemu waits in infinite loop to read a signal from gdb (when it waits on breakpoint for example). I added sleeps to reduce the cpu usage from 100% to about ~0%. Wouldn't it be better to toggle the O_NONBLOCK state of the file descriptor across this loop? r~ -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg
Re: [Qemu-devel] fixing qemu busy wait
Il 20/02/2013 20:39, Orr Dvory ha scritto: if (errno != EINTR errno != EAGAIN) +/* there's no need to restore the +O_NONBLOCK option. */ return; + But it's cleaner to do it anyway. :) Paolo
Re: [Qemu-devel] fixing qemu busy wait
On 2013-02-15 03:12, Orr Dvory wrote: when debugging with qemu(user mode), qemu waits in infinite loop to read a signal from gdb (when it waits on breakpoint for example). I added sleeps to reduce the cpu usage from 100% to about ~0%. Wouldn't it be better to toggle the O_NONBLOCK state of the file descriptor across this loop? r~
[Qemu-devel] fixing qemu busy wait
when debugging with qemu(user mode), qemu waits in infinite loop to read a signal from gdb (when it waits on breakpoint for example). I added sleeps to reduce the cpu usage from 100% to about ~0%. qemu-busy-wait.patch Description: Binary data
