On Wed, Nov 28, 2018 at 12:30:42PM +0100, Stefano Garzarella wrote:
On Wed, Nov 28, 2018 at 3:12 AM Kevin O'Connor kevin@koconnor.net wrote:
On Mon, Nov 26, 2018 at 12:39:12PM +0100, Stefano Garzarella wrote:
Speed up the boot phase when qemu uses "linuxboot" optionrom (qemu -kernel) and the boot-menu is not required. Under these conditions we can skip the setup of devices and VGA, because they will be initialized (if they are required) during the Linux boot phase.
Following the time measured between SeaBIOS entry point and "linuxboot" entry point:
Before this patch qemu -kernel | qemu -vga none -kernel --------------+----------------------- 53.5 msec | 23.34 msec
After this patch qemu -kernel | qemu -vga none -kernel --------------+----------------------- 12.82 msec | 10.89 msec
Note: For the measuring, we used the default configuration disabling debug messages (CONFIG_DEBUG_LEVEL=0) and applying Stephen's patch: "tpm: Check for TPM related ACPI tables before attempting hw"
Signed-off-by: Stefano Garzarella sgarzare@redhat.com
src/bootsplash.c | 3 +++ src/fw/paravirt.c | 10 ++++++++++ src/fw/paravirt.h | 4 ++++ src/optionroms.c | 3 ++- src/post.c | 3 +++ 5 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/src/bootsplash.c b/src/bootsplash.c index 165c98d..0eda7f2 100644 --- a/src/bootsplash.c +++ b/src/bootsplash.c @@ -8,6 +8,7 @@ #include "bregs.h" // struct bregs #include "config.h" // CONFIG_* #include "farptr.h" // FLATPTR_TO_SEG +#include "fw/paravirt.h" // runningOnQEMUFastBoot #include "malloc.h" // free #include "output.h" // dprintf #include "romfile.h" // romfile_loadfile @@ -39,6 +40,8 @@ call16_int10(struct bregs *br) void enable_vga_console(void) {
- if(runningOnQEMUFastBoot())
return;diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index 0770c47..9e6e618 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -621,4 +621,14 @@ void qemu_cfg_init(void) if (nogfx && !romfile_find("etc/sercon-port") && !romfile_find("vgaroms/sgabios.bin")) const_romfile_add_int("etc/sercon-port", PORT_SERIAL1);
- /*
* Enable QEMU fast boot if there is "linuxboot" optionrom and* the boot menu is not required.*/- if ((romfile_find("genroms/linuxboot_dma.bin")
|| romfile_find("genroms/linuxboot.bin"))&& !romfile_loadint("etc/show-boot-menu", 1)) {PlatformRunningOn |= PF_QEMU_FB;- }
I don't think we should hardcode special meanings to the names of bootable files. If QEMU wants SeaBIOS to not perform some type of hardware init, then I think QEMU should explicitly request that from SeaBIOS (eg, a "etc/dont-run-hardware-init").
I agree, it is cleaner. That was one of my doubt but, with an explicit request, it works only with a new version of QEMU. Do you think is acceptable?
It would be good to understand what the source of the delay is. It might be possible to avoid the delay without adding a new config setting. For example, the patch above will prevent the vga rom from being run, but it should be possible to accomplish the same with "-device VGA,romfile=". The other change this patch makes is to skip device_hardware_setup() - is it known which items in that function add to the delay?
Also, what is the target boot time that is considered acceptable?
Thanks, -Kevin
On Wed, Nov 28, 2018 at 3:38 PM Kevin O'Connor kevin@koconnor.net wrote:
On Wed, Nov 28, 2018 at 12:30:42PM +0100, Stefano Garzarella wrote:
On Wed, Nov 28, 2018 at 3:12 AM Kevin O'Connor kevin@koconnor.net wrote:
On Mon, Nov 26, 2018 at 12:39:12PM +0100, Stefano Garzarella wrote:
Speed up the boot phase when qemu uses "linuxboot" optionrom (qemu -kernel) and the boot-menu is not required. Under these conditions we can skip the setup of devices and VGA, because they will be initialized (if they are required) during the Linux boot phase.
Following the time measured between SeaBIOS entry point and "linuxboot" entry point:
Before this patch qemu -kernel | qemu -vga none -kernel --------------+----------------------- 53.5 msec | 23.34 msec
After this patch qemu -kernel | qemu -vga none -kernel --------------+----------------------- 12.82 msec | 10.89 msec
Note: For the measuring, we used the default configuration disabling debug messages (CONFIG_DEBUG_LEVEL=0) and applying Stephen's patch: "tpm: Check for TPM related ACPI tables before attempting hw"
Signed-off-by: Stefano Garzarella sgarzare@redhat.com
src/bootsplash.c | 3 +++ src/fw/paravirt.c | 10 ++++++++++ src/fw/paravirt.h | 4 ++++ src/optionroms.c | 3 ++- src/post.c | 3 +++ 5 files changed, 22 insertions(+), 1 deletion(-)
diff --git a/src/bootsplash.c b/src/bootsplash.c index 165c98d..0eda7f2 100644 --- a/src/bootsplash.c +++ b/src/bootsplash.c @@ -8,6 +8,7 @@ #include "bregs.h" // struct bregs #include "config.h" // CONFIG_* #include "farptr.h" // FLATPTR_TO_SEG +#include "fw/paravirt.h" // runningOnQEMUFastBoot #include "malloc.h" // free #include "output.h" // dprintf #include "romfile.h" // romfile_loadfile @@ -39,6 +40,8 @@ call16_int10(struct bregs *br) void enable_vga_console(void) {
- if(runningOnQEMUFastBoot())
return;diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c index 0770c47..9e6e618 100644 --- a/src/fw/paravirt.c +++ b/src/fw/paravirt.c @@ -621,4 +621,14 @@ void qemu_cfg_init(void) if (nogfx && !romfile_find("etc/sercon-port") && !romfile_find("vgaroms/sgabios.bin")) const_romfile_add_int("etc/sercon-port", PORT_SERIAL1);
- /*
* Enable QEMU fast boot if there is "linuxboot" optionrom and* the boot menu is not required.*/- if ((romfile_find("genroms/linuxboot_dma.bin")
|| romfile_find("genroms/linuxboot.bin"))&& !romfile_loadint("etc/show-boot-menu", 1)) {PlatformRunningOn |= PF_QEMU_FB;- }
I don't think we should hardcode special meanings to the names of bootable files. If QEMU wants SeaBIOS to not perform some type of hardware init, then I think QEMU should explicitly request that from SeaBIOS (eg, a "etc/dont-run-hardware-init").
I agree, it is cleaner. That was one of my doubt but, with an explicit request, it works only with a new version of QEMU. Do you think is acceptable?
It would be good to understand what the source of the delay is. It might be possible to avoid the delay without adding a new config setting. For example, the patch above will prevent the vga rom from being run, but it should be possible to accomplish the same with "-device VGA,romfile=". The other change this patch makes is to skip device_hardware_setup() - is it known which items in that function add to the delay?
Hi Kevin, thanks for your advice.
I tried to understand what are the sources of the delay, and I found that most of the time is spent because of QEMU default devices (eg e1000 ROM PCI, mouse, keyboard, etc) At this point, (without the patch above) I disabled the default QEMU devices (-nodefaults) and I reached 12.5 ms of SeaBIOS boot time (compared to 22 ms, where 4 ms is taken by the loading of e1000 ROM).
Other 2 ms is taken by enable_vga_console(), where simply comment out the printf("SeaBIOS (version %s)\n", VERSION) I reached 10.7 ms of boot time. Do you think is acceptable to use dprintf(1, ...) instead of printf()? Or maybe check if we found the VGA.
Note: All these tests are done with CONFIG_DEBUG_LEVEL=0, using CONFIG_DEBUG_LEVEL=1 the boot time grows up to 24 ms, maybe we should put CONFIG_DEBUG_LEVEL=0 in the SeaBIOS configuration used in QEMU.
Also, what is the target boot time that is considered acceptable?
I'm using qboot as a reference (6/7 ms). It is very minimal, so 10 ms I think is considered acceptable for SeaBIOS
Thanks, Stefano
Thanks, -Kevin--
Stefano Garzarella Red Hat
-
Kevin O'Connor -
Stefano Garzarella