bsd-user/main.c | 9 +++++++++ 1 file changed, 9 insertions(+)
While qemu-system can set tb-size using -accel tcg,tb-size=n, there
is no similar knob for qemu-bsd-user. Add one in a way similar to how
one-insn-per-tb is already handled.
Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
bsd-user/main.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/bsd-user/main.c b/bsd-user/main.c
index cc980e6f401..7c230b0c7a5 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -60,6 +60,7 @@ uintptr_t qemu_host_page_size;
intptr_t qemu_host_page_mask;
static bool opt_one_insn_per_tb;
+static unsigned long opt_tb_size;
uintptr_t guest_base;
bool have_guest_base;
/*
@@ -169,6 +170,7 @@ static void usage(void)
" (use '-d help' for a list of log items)\n"
"-D logfile write logs to 'logfile' (default stderr)\n"
"-one-insn-per-tb run with one guest instruction per emulated TB\n"
+ "-tb-size size TCG translation block cache size\n"
"-strace log system calls\n"
"-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
" specify tracing options\n"
@@ -387,6 +389,11 @@ int main(int argc, char **argv)
seed_optarg = optarg;
} else if (!strcmp(r, "one-insn-per-tb")) {
opt_one_insn_per_tb = true;
+ } else if (!strcmp(r, "tb-size")) {
+ r = argv[optind++];
+ if (qemu_strtoul(r, NULL, 0, &opt_tb_size)) {
+ usage();
+ }
} else if (!strcmp(r, "strace")) {
do_strace = 1;
} else if (!strcmp(r, "trace")) {
@@ -452,6 +459,8 @@ int main(int argc, char **argv)
accel_init_interfaces(ac);
object_property_set_bool(OBJECT(accel), "one-insn-per-tb",
opt_one_insn_per_tb, &error_abort);
+ object_property_set_int(OBJECT(accel), "tb-size",
+ opt_tb_size, &error_abort);
ac->init_machine(NULL);
}
--
2.45.2
On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
> While qemu-system can set tb-size using -accel tcg,tb-size=n, there
> is no similar knob for qemu-bsd-user. Add one in a way similar to how
> one-insn-per-tb is already handled.
>
Cool! Are you using bsd-user and need this for some reason? Or is this
purely theoretical? Is there a larger context I can read about somewhere?
I'll merge it either way (so none of the above is a criticism, I'm genuinely
curious) , but I don't get too many bsd-user fixes and this one is unusual.
> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
> bsd-user/main.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index cc980e6f401..7c230b0c7a5 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -60,6 +60,7 @@ uintptr_t qemu_host_page_size;
> intptr_t qemu_host_page_mask;
>
> static bool opt_one_insn_per_tb;
> +static unsigned long opt_tb_size;
> uintptr_t guest_base;
> bool have_guest_base;
> /*
> @@ -169,6 +170,7 @@ static void usage(void)
> " (use '-d help' for a list of log items)\n"
> "-D logfile write logs to 'logfile' (default stderr)\n"
> "-one-insn-per-tb run with one guest instruction per emulated
> TB\n"
> + "-tb-size size TCG translation block cache size\n"
> "-strace log system calls\n"
> "-trace
> [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
> " specify tracing options\n"
> @@ -387,6 +389,11 @@ int main(int argc, char **argv)
> seed_optarg = optarg;
> } else if (!strcmp(r, "one-insn-per-tb")) {
> opt_one_insn_per_tb = true;
> + } else if (!strcmp(r, "tb-size")) {
> + r = argv[optind++];
> + if (qemu_strtoul(r, NULL, 0, &opt_tb_size)) {
> + usage();
> + }
> } else if (!strcmp(r, "strace")) {
> do_strace = 1;
> } else if (!strcmp(r, "trace")) {
> @@ -452,6 +459,8 @@ int main(int argc, char **argv)
> accel_init_interfaces(ac);
> object_property_set_bool(OBJECT(accel), "one-insn-per-tb",
> opt_one_insn_per_tb, &error_abort);
> + object_property_set_int(OBJECT(accel), "tb-size",
> + opt_tb_size, &error_abort);
> ac->init_machine(NULL);
> }
>
Reviewed-by: Warner Losh <imp@bsdimp.com>
I'll queue this to my bsd-user-2024-q3-2 branch. I hope to land it, just
after 9.1.0 release.
Warner
On Wed, 2024-07-31 at 15:21 -0600, Warner Losh wrote: > On Wed, Jul 31, 2024 at 8: 45 AM Ilya Leoshkevich > <iii@ linux. ibm. com> wrote: While qemu-system can set tb-size using > -accel tcg,tb-size=n, there is no similar knob for qemu-bsd-user. Add > one in a way similar to how one-insn-per-tb is already > > > > On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com> > wrote: > > While qemu-system can set tb-size using -accel tcg,tb-size=n, there > > is no similar knob for qemu-bsd-user. Add one in a way similar to > > how > > one-insn-per-tb is already handled. > > > > > Cool! Are you using bsd-user and need this for some reason? Or is > this > purely theoretical? Is there a larger context I can read about > somewhere? I needed this on Linux in order to debug an issue where I suspected full TB invalidation may be an issue. It turned out to be something completely different, but I found it useful: setting it to, e.g., 4096 makes full TB invalidation very rare, so if a problem is still reproducible, then the root causes is something else. Philippe suggested to implement this for BSD as well in order to keep the interfaces in sync. [...]
On Thu, Aug 1, 2024 at 2:25 AM Ilya Leoshkevich <iii@linux.ibm.com> wrote: > On Wed, 2024-07-31 at 15:21 -0600, Warner Losh wrote: > > On Wed, Jul 31, 2024 at 8: 45 AM Ilya Leoshkevich <iii@ linux. ibm. com> > wrote: While qemu-system can set tb-size using -accel tcg,tb-size=n, there > is no similar knob for qemu-bsd-user. Add one in a way similar to how > one-insn-per-tb is already > On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com> > wrote: > > While qemu-system can set tb-size using -accel tcg,tb-size=n, there > is no similar knob for qemu-bsd-user. Add one in a way similar to how > one-insn-per-tb is already handled. > > > Cool! Are you using bsd-user and need this for some reason? Or is this > purely theoretical? Is there a larger context I can read about somewhere? > > > I needed this on Linux in order to debug an issue where I suspected full > TB invalidation may be an issue. > It turned out to be something completely different, but I found it useful: > setting it to, e.g., 4096 makes full TB invalidation very rare, so if a > problem is still reproducible, then the root causes is something else. > Philippe suggested to implement this for BSD as well in order to keep the > interfaces in sync. > Excellent! Thank you for taking the time to do this! And the other bug fix. Both have been queued to my first post 9.1 pull branch. Warner
On 31/7/24 23:21, Warner Losh wrote: > On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com > <mailto:iii@linux.ibm.com>> wrote: > > While qemu-system can set tb-size using -accel tcg,tb-size=n, there > is no similar knob for qemu-bsd-user. Add one in a way similar to how > one-insn-per-tb is already handled. > > > Cool! Are you using bsd-user and need this for some reason? Or is this > purely theoretical? Is there a larger context I can read about somewhere? Trying to keep user interface parity between linux/bsd. Ideally this duplication should be unified in common-user/. > I'll merge it either way (so none of the above is a criticism, I'm genuinely > curious) , but I don't get too many bsd-user fixes and this one is unusual. > > Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org > <mailto:philmd@linaro.org>> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com > <mailto:iii@linux.ibm.com>> > --- > bsd-user/main.c | 9 +++++++++ > 1 file changed, 9 insertions(+)
On Wed, Jul 31, 2024 at 3:42 PM Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > On 31/7/24 23:21, Warner Losh wrote: > > On Wed, Jul 31, 2024 at 8:45 AM Ilya Leoshkevich <iii@linux.ibm.com > > <mailto:iii@linux.ibm.com>> wrote: > > > > While qemu-system can set tb-size using -accel tcg,tb-size=n, there > > is no similar knob for qemu-bsd-user. Add one in a way similar to how > > one-insn-per-tb is already handled. > > > > > > Cool! Are you using bsd-user and need this for some reason? Or is this > > purely theoretical? Is there a larger context I can read about somewhere? > > Trying to keep user interface parity between linux/bsd. > > Ideally this duplication should be unified in common-user/. > I'd love that. Anyway, both of these patches queued to my branch > > I'll merge it either way (so none of the above is a criticism, I'm > genuinely > > curious) , but I don't get too many bsd-user fixes and this one is > unusual. > > > > Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org > > <mailto:philmd@linaro.org>> > > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com > > <mailto:iii@linux.ibm.com>> > > --- > > bsd-user/main.c | 9 +++++++++ > > 1 file changed, 9 insertions(+) > >
On 31/7/24 16:45, Ilya Leoshkevich wrote: > While qemu-system can set tb-size using -accel tcg,tb-size=n, there > is no similar knob for qemu-bsd-user. Add one in a way similar to how > one-insn-per-tb is already handled. > > Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > bsd-user/main.c | 9 +++++++++ > 1 file changed, 9 insertions(+) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
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