Ping. Any feedback on these two patches?
https://patchew.org/QEMU/20230205163758.416992-1-c...@braap.org/
https://lore.kernel.org/qemu-devel/20230205163758.416992-1-c...@braap.org/
Happy to resend if needed.
Thanks,
Emilio
On Fri, Feb 17, 2023 at 07:44:38 -0500, Emilio Cota
; *: Add missing includes of qemu/error-report.h
> *: Add missing includes of qemu/plugin.h
> include/qemu: Split out plugin-event.h
> include/qemu/plugin: Inline qemu_plugin_disable_mem_helpers
Reviewed-by: Emilio Cota
Thanks, Richard!
Alex: is it too late to ad
On Wed, Feb 15, 2023 at 20:15:37 -1000, Richard Henderson wrote:
> On 2/10/23 02:35, Emilio Cota wrote:
> > I ran yesterday linux-user SPEC06 benchmarks from your tcg-life branch.
> > I do see perf regressions for two workloads (sjeng and xalancbmk).
> > With perf(1
As I mentioned in the patch that is being superseded here
I like this approach -- it is simpler and generates less
code.
I'd also like to see the plugin_gen_disable_mem_helpers
function go away, and a mention somewhere that now we are
intentionally not clearing cpu->plugin_mem_cbs until TB exit
On Tue, Feb 28, 2023 at 10:50:26 -1000, Richard Henderson wrote:
> On 2/21/23 18:32, Emilio Cota wrote:
> > Currently we are wrongly accessing plugin_tb->mem_helper at
> > translation time from plugin_gen_disable_mem_helpers, which is
> > called before generating a TB
lt;-- after_insn clearing (dead)
set_label $L0
mov_i64 tmp2,$0x0
st_i64 tmp2,env,$0xef68 <-- before_exit clearing (doesn't matter
due to $L0)
exit_tb $0x7f38c843
[...]
Fixes: #1381
Signed-off-by: Emilio Cota
---
accel/tcg/plugin-gen.c| 44 --
Ping.
This fixes a bug (admittedly with a big hammer) that affects
users with heavily multi-threaded user-mode workloads.
Thanks,
Emilio
On Sun, Feb 05, 2023 at 11:37:56 -0500, Emilio Cota wrote:
> Changes since v1:
>
> - Add configure check to only use QTree if G
Hi Richard,
On Mon, Jan 30, 2023 at 10:59:07 -1000, Richard Henderson wrote:
(snip)
> With this, and by not recycling TEMP_LOCAL, we can get identical code
> out of the backend even when changing the front end translators are
> adjusted to use TEMP_LOCAL for everything.
>
> Benchmarking one test
On Mon, Jan 30, 2023 at 09:09:47 -1000, Richard Henderson wrote:
> On 1/29/23 23:27, Daniel P. Berrangé wrote:
> > On Sun, Jan 29, 2023 at 05:38:08PM -0500, Emilio Cota wrote:
> > > Since this is a correctness issue, I think we should ship with qtree
> > > and use it
.68 276.05 266.75 251.65
104.93
QTree Traverse 278.31 (1.00x) 275.78 (1.00x) 266.42 (1.00x) 247.89
(0.99x) 104.58 (1.00x)
Related: #285
Signed-off-by: Emilio C
Changes since v1:
- Add configure check to only use QTree if Glib still implements gslice.
If Glib doesn't, then we call Glib directly with inline functions.
- Add TODO's so that in the future (i.e. when the minimum version of
Glib that we use doesn't implement gslice) we remove QTree.
- Add
wstatus;
waitpid(pid, , 0);
}
}
void supragarble(unsigned depth) {
if (depth == 0)
return ;
std::thread a(supragarble, depth-1);
std::thread b(supragarble, depth-1);
garble();
a.join();
b.join();
}
int main() {
supragarble(10);
}
```
Fixes: #285
Signed-off-by: Emilio Cota
On Wed, Jan 11, 2023 at 12:08:26 +, Daniel P. Berrangé wrote:
> First, I find the test to be a little unreliable the first few
> times it is ran. I ran it in a loop 20 times and it got more
> stable results. Looking at just the QTree lines I get something
> typically like:
Agreed, this is a
On Wed, Jan 25, 2023 at 15:58:25 +, Daniel P. Berrangé wrote:
> On Wed, Jan 11, 2023 at 12:34:29PM +, Daniel P. Berrangé wrote:
> > On Tue, Jan 10, 2023 at 10:55:36PM -0500, Emilio Cota wrote:
> > > qemu-user can hang in a multi-threaded fork. One common
> > > r
On Wed, Jan 11, 2023 at 12:10:53 +, Daniel P. Berrangé wrote:
> On Tue, Jan 10, 2023 at 10:55:36PM -0500, Emilio Cota wrote:
> > Performance impact on linux-user:
> > - ~2% slowdown in spec06
> > - 1.05% slowdown in Nbench-int
> > - 4.51% slowdown in Nbench-fp
&
On Thu, Dec 01, 2022 at 10:49:27 +, Alex Bennée wrote:
> Emilio Cota writes:
> > On Tue, Oct 04, 2022 at 13:00:47 +0100, Daniel P. Berrangé wrote:
> > (snip)
> >> Can't say I especially like this but I'm out of other ideas for how
> >> to guarantee a solutio
To fix potential deadlocks as reported by tsan.
Reviewed-by: Richard Henderson
Reviewed-by: Philippe Mathieu-Daudé
Signed-off-by: Emilio Cota
---
plugins/core.c | 16 +++-
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/plugins/core.c b/plugins/core.c
index
Changes since v2:
- Add R-b's
- patch 4/5: Fix incompatible pointer type errors
- patch 4/5: Remove leftover helper
Thanks,
Emilio
ibc-start.c:392 (libc.so.6+0x29e3f)
#24 _start (test-qht+0xdb44)
Signed-off-by: Emilio Cota
---
util/qht.c | 95 ++
1 file changed, 81 insertions(+), 14 deletions(-)
diff --git a/util/qht.c b/util/qht.c
index 15866299e6..92c6b78759 100644
We forgot to add this one in "a890643958 util/qht: atomically set b->hashes".
Detected with tsan.
Reviewed-by: Richard Henderson
Reviewed-by: Philippe Mathieu-Daudé
Reviewed-by: Alex Bennée
Signed-off-by: Emilio Cota
---
util/qht.c | 2 +-
1 file changed, 1 insertion(+), 1 dele
Reviewed-by: Alex Bennée
Signed-off-by: Emilio Cota
---
include/qemu/thread.h | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index 7c6703bce3..7841084199 100644
--- a/include/qemu/thread.h
+++ b/include/qemu/thread.h
T148 here:
#0 0x7f49627b6460 in __interceptor_free
../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:52
#1 0x5593da5ac057 in cpu_exec_unrealizefn ../cpu.c:180
#2 0x5593da81f851 (/home/cota/src/qemu/build/qemu-x86_64+0x484851)
Signed-off-by: Emilio Cota
---
accel/tcg/cpu-exec.c
+-|
| + ***|
13 ++
master-gcc12 qtree-gcc12
QEMU version
Signed-off-by: Emilio Cota
---
accel/tcg/tb-maint.c | 17
) 62.25 (0.68x)
Signed-off-by: Emilio Cota
---
include/qemu/qtree.h | 119 +++
tests/bench/meson.build |4 +
tests/bench/qtree-bench.c | 273 ++
tests/unit/meson.build|1
Context:
https://gitlab.com/qemu-project/qemu/-/issues/285
So far the only fix that we have had posted on the list is
https://lists.gnu.org/archive/html/qemu-devel/2022-10/msg00391.html
by Daniel. The approach that I'm following here should have
the same outcome, except that it doesn't change
On Tue, Jan 10, 2023 at 20:58:01 +, Alex Bennée wrote:
> Emilio Cota writes:
(snip)
> > +static inline void qht_do_if_first_in_stripe(const struct qht_map *map,
> > + struct qht_bucket *b,
> > +
On Mon, Jan 09, 2023 at 13:52:36 +, Alex Bennée wrote:
> Emilio Cota writes:
> > --- a/accel/tcg/cpu-exec.c
> > +++ b/accel/tcg/cpu-exec.c
> > @@ -504,6 +504,7 @@ static void cpu_exec_exit(CPUState *cpu)
> > if (cc->tcg_ops->cpu_exec_exit) {
> >
Changes since v1:
- call g_free_rcu on tb_jmp_cache directly, and call
tcg_exec_unrealizefn after calling cpu_list_remove(cpu)
- add patch to de-const qemu_spin_destroy
- remove wrappers for qht_do_if_first_in_stripe
Thanks,
Emilio
ibc-start.c:392 (libc.so.6+0x29e3f)
#24 _start (test-qht+0xdb44)
Signed-off-by: Emilio Cota
---
util/qht.c | 101 +
1 file changed, 87 insertions(+), 14 deletions(-)
diff --git a/util/qht.c b/util/qht.c
index 15866299e6..70cc733d5d 100644
To fix potential deadlocks as reported by tsan.
Reviewed-by: Richard Henderson
Signed-off-by: Emilio Cota
---
plugins/core.c | 16 +++-
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/plugins/core.c b/plugins/core.c
index ccb770a485..728bacef95 100644
--- a/plugins
Signed-off-by: Emilio Cota
---
include/qemu/thread.h | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index 7c6703bce3..7841084199 100644
--- a/include/qemu/thread.h
+++ b/include/qemu/thread.h
@@ -237,11 +237,10 @@ static
We forgot to add this one in "a890643958 util/qht: atomically set b->hashes".
Detected with tsan.
Reviewed-by: Richard Henderson
Reviewed-by: Philippe Mathieu-Daudé
Signed-off-by: Emilio Cota
---
util/qht.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/util
T148 here:
#0 0x7f49627b6460 in __interceptor_free
../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:52
#1 0x5593da5ac057 in cpu_exec_unrealizefn ../cpu.c:180
#2 0x5593da81f851 (/home/cota/src/qemu/build/qemu-x86_64+0x484851)
Signed-off-by: Emilio Cota
---
accel/tcg/cpu-exec.c
On Sun, Jan 08, 2023 at 11:19:53 -0800, Richard Henderson wrote:
> On 1/8/23 08:39, Emilio Cota wrote:
(snip)
> > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
> > index 356fe348de..ca95d21528 100644
> > --- a/accel/tcg/cpu-exec.c
> > +++ b/accel/tcg/cpu-ex
On Sun, Jan 08, 2023 at 11:51:44 -0800, Richard Henderson wrote:
> On 1/8/23 08:39, Emilio Cota wrote:
> > +static inline void qht_bucket_lock_init(const struct qht_map *map,
> > +struct qht_bucket *b)
> > +{
> > +qht_d
Fixes: #1381
Signed-off-by: Emilio Cota
---
accel/tcg/cpu-exec.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 356fe348de..de4ba6e23c 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -504,6 +504,7 @@ static void
Related: #1381
Signed-off-by: Emilio Cota
---
accel/tcg/translator.c | 15 ++-
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 061519691f..ef5193c67e 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
It is internal to TCG and therefore we know it does not
access guest memory.
Related: #1381
Signed-off-by: Emilio Cota
---
tcg/tcg.c | 6 --
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/tcg/tcg.c b/tcg/tcg.c
index da91779890..ee67eefc0c 100644
--- a/tcg/tcg.c
+++ b/tcg
earing cpu->plugin_mem_cbs) way too often,
since it's not rare that the last instruction in the TB doesn't
use helpers.
Fix it by tracking a per-TB canary.
While at it, expand documentation.
Related: #1381
Signed-off-by: Emilio Cota
---
accel/tcg/plugin-gen.c | 26 ++
Hi,
These are the plugin fixes that I mentioned here:
https://lists.gnu.org/archive/html/qemu-devel/2022-12/msg02865.html
They should fix https://gitlab.com/qemu-project/qemu/-/issues/1381
Thanks,
Emilio
ibc-start.c:392 (libc.so.6+0x29e3f)
#24 _start (test-qht+0xdb44)
Signed-off-by: Emilio Cota
---
util/qht.c | 107 ++---
1 file changed, 93 insertions(+), 14 deletions(-)
diff --git a/util/qht.c b/util/qht.c
index 15866299e6..6174533f10 100644
We forgot to add this one in "a890643958 util/qht: atomically set b->hashes".
Detected with tsan.
Signed-off-by: Emilio Cota
---
util/qht.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/util/qht.c b/util/qht.c
index 065fc501f4..15866299e6 100644
--- a/uti
To fix potential deadlocks as reported by tsan.
Signed-off-by: Emilio Cota
---
plugins/core.c | 16 +++-
1 file changed, 11 insertions(+), 5 deletions(-)
diff --git a/plugins/core.c b/plugins/core.c
index ccb770a485..728bacef95 100644
--- a/plugins/core.c
+++ b/plugins/core.c
Hi,
Here are some fixes for tsan issues that I've encountered.
The most important patch is 3/4, which allows us to run tsan for
non-trivial workloads.
Thanks,
Emilio
T148 here:
#0 0x7f49627b6460 in __interceptor_free
../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:52
#1 0x5593da5ac057 in cpu_exec_unrealizefn ../cpu.c:180
#2 0x5593da81f851 (/home/cota/src/qemu/build/qemu-x86_64+0x484851)
Signed-off-by: Emilio Cota
---
accel/tcg/cpu-exec.c
On Fri, Jan 6, 2023, 5:31 AM Alex Bennée wrote:
> Are you going to be able to post the patches soon? I'd like to get the
> fixes in as early in the cycle as possible.
>
I intend to post this series on Sunday.
Thanks,
Emilio
On Tue, Nov 29, 2022 at 15:37:51 -0500, Aaron Lindsay wrote:
(snip)
> > Does this hint that there are cases where reset cpu->plugin_mem_cbs to NULL
> > is
> > getting optimized away, but not the code to set it in the first place?
>
> Is there anyone who could help take a look at this from the
On Tue, Oct 04, 2022 at 13:00:47 +0100, Daniel P. Berrangé wrote:
(snip)
> Can't say I especially like this but I'm out of other ideas for how
> to guarantee a solution. Users can't set env vars prior to launching
> QEMU user emulators when using binfmt.
An alternative is to not use GSlice
On Tue, Nov 15, 2022 at 22:36:07 +, Alex Bennée wrote:
> This is exactly the sort of thing rr is great for. Can you trigger it in
> that?
>
> https://rr-project.org/
The sanitizers should also help.
For TLB flush tracing, defining DEBUG_TLB at the top of cputlb.c
might be useful.
(Sorry if this comes out garbled, I'm on a web editor not a proper email client)
On Fri, Feb 4, 2022 at 3:49 PM Alex Bennée wrote:
> +typedef struct {
> +uint64_t last_pc;
> +uint64_t insn_count;
> +} InstructionCount;
This will need padding to take up a cache line.
> +static
On Thu, Dec 2, 2021 at 4:47 AM Vasilev Oleg wrote:
> The mentioned paper[4] also describes other possible improvements.
> Some of those are already implemented (such as victim TLB and dynamic
> size for TLB), but others are not (e.g. TLB lookup uninlining and
> set-associative TLB layer). Do you
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