| Message ID | 1467272240-32123-7-git-send-email-pl@kamp.de |
|---|---|
| State | New |
| Headers | show |
On 06/30/2016 12:37 AM, Peter Lieven wrote: > evaluation with the recently introduced maximum stack usage monitoring revealed > that the actual used stack size was never above 4kB so allocating 1MB stack > for each coroutine is a lot of wasted memory. So reduce the stack size to > 64kB which should still give enough head room. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > include/qemu/coroutine_int.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h > index eac323a..f84d777 100644 > --- a/include/qemu/coroutine_int.h > +++ b/include/qemu/coroutine_int.h > @@ -28,7 +28,7 @@ > #include "qemu/queue.h" > #include "qemu/coroutine.h" > > -#define COROUTINE_STACK_SIZE (1 << 20) > +#define COROUTINE_STACK_SIZE (1 << 16) > > typedef enum { > COROUTINE_YIELD = 1, > Ought we check that this is not smaller than sysconf(_SC_THREAD_STACK_MIN) which (for glibc at least), is 192k for ia64, 128k for aarch64, mips and tile (though why it is quite so high in those later cases I don't know). r~
Am 01.07.2016 um 23:13 schrieb Richard Henderson: > On 06/30/2016 12:37 AM, Peter Lieven wrote: >> evaluation with the recently introduced maximum stack usage monitoring revealed >> that the actual used stack size was never above 4kB so allocating 1MB stack >> for each coroutine is a lot of wasted memory. So reduce the stack size to >> 64kB which should still give enough head room. >> >> Signed-off-by: Peter Lieven <pl@kamp.de> >> --- >> include/qemu/coroutine_int.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h >> index eac323a..f84d777 100644 >> --- a/include/qemu/coroutine_int.h >> +++ b/include/qemu/coroutine_int.h >> @@ -28,7 +28,7 @@ >> #include "qemu/queue.h" >> #include "qemu/coroutine.h" >> >> -#define COROUTINE_STACK_SIZE (1 << 20) >> +#define COROUTINE_STACK_SIZE (1 << 16) >> >> typedef enum { >> COROUTINE_YIELD = 1, >> > > Ought we check that this is not smaller than > > sysconf(_SC_THREAD_STACK_MIN) > > which (for glibc at least), is 192k for ia64, 128k for aarch64, mips and tile (though why it is quite so high in those later cases I don't know). for x86_64 it seems to be 16k. I would not mind to adjust the stack size either in qemu_alloc_stack or change the macro for the coroutine stack size into a function returning MAX(1 << 16, sysconf(_SC_THREAD_STACK_MIN)). Peter
On 04/07/2016 08:22, Peter Lieven wrote: >>> >> >> Ought we check that this is not smaller than >> >> sysconf(_SC_THREAD_STACK_MIN) >> >> which (for glibc at least), is 192k for ia64, 128k for aarch64, mips >> and tile (though why it is quite so high in those later cases I don't >> know). > > for x86_64 it seems to be 16k. I would not mind to adjust the stack size > either in qemu_alloc_stack or change the macro for the coroutine stack > size into a function returning MAX(1 << 16, sysconf(_SC_THREAD_STACK_MIN)). Yes, either of this is a good idea. Paolo
diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h index eac323a..f84d777 100644 --- a/include/qemu/coroutine_int.h +++ b/include/qemu/coroutine_int.h @@ -28,7 +28,7 @@ #include "qemu/queue.h" #include "qemu/coroutine.h" -#define COROUTINE_STACK_SIZE (1 << 20) +#define COROUTINE_STACK_SIZE (1 << 16) typedef enum { COROUTINE_YIELD = 1,
evaluation with the recently introduced maximum stack usage monitoring revealed that the actual used stack size was never above 4kB so allocating 1MB stack for each coroutine is a lot of wasted memory. So reduce the stack size to 64kB which should still give enough head room. Signed-off-by: Peter Lieven <pl@kamp.de> --- include/qemu/coroutine_int.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)