From: "Gerd Möllmann" <gerd.moellmann@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: yantar92@posteo.net, emacs-devel@gnu.org, eller.helmut@gmail.com
Subject: Re: MPS: profiler
Date: Fri, 21 Jun 2024 09:32:00 +0200 [thread overview]
Message-ID: <m2zfre4uq7.fsf@pro2.fritz.box> (raw)
In-Reply-To: <86tthmlq98.fsf@gnu.org> (Eli Zaretskii's message of "Fri, 21 Jun 2024 10:16:35 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>> Cc: Ihor Radchenko <yantar92@posteo.net>, emacs-devel@gnu.org,
>> eller.helmut@gmail.com
>> Date: Fri, 21 Jun 2024 08:54:34 +0200
>>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>> > Also, can 'static struct profiler_log cpu', which is being worked on
>> > by record_backtrace, be affected by MPS in any way?
>>
>> I'd guess that just "touching" Lisp objects in the SIGPROF handler can
>> be problematic because these objects themselves can be behind a barrier,
>> either the same that MPS is currently working on when it got interrupted
>> or another one.
>
> Which Lisp objects do we touch in record_backtrace? All I see is that
> we access spec_pdl and its data. Is that supposed to be dangerous
> while MPS does its thing?
I don't know. In the backtrace I commented on in a reply to Ihor, we had
this:
#0 0x00005555558b53d6 in PSEUDOVECTORP (a=0x7fffe6dde715, code=32) at /home/yantar92/Git/emacs/src/lisp.h:1104
#1 0x00005555558b567f in CLOSUREP (a=0x7fffe6dde715) at /home/yantar92/Git/emacs/src/lisp.h:3368
#2 0x00005555558b5b80 in trace_hash (trace=0x555556329400, depth=16) at profiler.c:189
>
> Also note that add_sample (called by the SIGPROF handler) does this:
>
> if (EQ (backtrace_top_function (), QAutomatic_GC)) /* bug#60237 */
> /* Special case the time-count inside GC because the hash-table
> code is not prepared to be used while the GC is running.
> More specifically it uses ASIZE at many places where it does
> not expect the ARRAY_MARK_FLAG to be set. We could try and
> harden the hash-table code, but it doesn't seem worth the
> effort. */
> plog->gc_count = saturated_add (plog->gc_count, count);
> else
> record_backtrace (plog, count);
>
> IOW, it avoids recording the backtrace if called during GC. Perhaps
> we should do the same with igc? Or doe we already set up
> backtrace_top_function to return QAutomatic_GC in that case?
I don't think we do. I'm not even sure we could do that reliably since
MPS is running concurrently.
> And finally, I see in make_log that we already do something about the
> log variables that is specific to MPS. Is that not enough to prevent
> this kind of issues?
No, that's just making sure we trace what's in the malloc'd memory.
next prev parent reply other threads:[~2024-06-21 7:32 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-20 19:25 MPS: profiler Ihor Radchenko
2024-06-20 19:40 ` Eli Zaretskii
2024-06-20 19:48 ` Ihor Radchenko
2024-06-20 19:58 ` Gerd Möllmann
2024-06-20 20:29 ` Ihor Radchenko
2024-06-21 5:57 ` Gerd Möllmann
2024-06-21 6:17 ` Eli Zaretskii
2024-06-21 6:54 ` Gerd Möllmann
2024-06-21 7:16 ` Eli Zaretskii
2024-06-21 7:32 ` Gerd Möllmann [this message]
2024-06-21 7:19 ` Helmut Eller
2024-06-21 7:36 ` Ihor Radchenko
2024-06-21 7:44 ` Helmut Eller
2024-06-21 7:51 ` Gerd Möllmann
2024-06-21 8:21 ` Helmut Eller
2024-06-21 8:31 ` Gerd Möllmann
2024-06-21 10:45 ` Eli Zaretskii
2024-06-21 11:47 ` Gerd Möllmann
2024-06-21 12:01 ` Helmut Eller
2024-06-21 12:09 ` Ihor Radchenko
2024-06-21 12:42 ` Helmut Eller
2024-06-21 12:51 ` Ihor Radchenko
2024-06-21 14:49 ` MPS make-thread (was: MPS: profiler) Helmut Eller
2024-06-21 15:20 ` MPS make-thread Gerd Möllmann
2024-06-21 15:33 ` Gerd Möllmann
2024-06-21 15:42 ` Helmut Eller
2024-06-21 16:46 ` Gerd Möllmann
2024-06-21 18:31 ` Gerd Möllmann
2024-06-21 19:58 ` Ihor Radchenko
2024-06-21 20:10 ` Gerd Möllmann
2024-06-22 18:52 ` Ihor Radchenko
2024-06-22 19:17 ` Eli Zaretskii
2024-06-23 3:18 ` Gerd Möllmann
2024-06-23 4:54 ` Gerd Möllmann
2024-06-23 6:19 ` Eli Zaretskii
2024-06-23 5:53 ` Eli Zaretskii
2024-06-23 6:45 ` Gerd Möllmann
2024-06-23 8:53 ` Eli Zaretskii
2024-06-23 9:36 ` Gerd Möllmann
2024-06-23 10:21 ` Gerd Möllmann
2024-06-23 10:27 ` Gerd Möllmann
2024-06-23 13:19 ` Eli Zaretskii
2024-06-23 14:16 ` Gerd Möllmann
2024-06-26 11:20 ` Ihor Radchenko
2024-06-26 11:25 ` Gerd Möllmann
2024-06-22 19:26 ` Gerd Möllmann
2024-06-22 6:29 ` Eli Zaretskii
2024-06-22 18:53 ` Ihor Radchenko
2024-06-22 19:04 ` Eli Zaretskii
2024-06-22 19:17 ` Ihor Radchenko
2024-06-22 18:13 ` Helmut Eller
2024-06-22 18:31 ` Gerd Möllmann
2024-06-25 18:42 ` MPS native subrs (was: MPS make-thread) Helmut Eller via Emacs development discussions.
2024-06-25 20:10 ` MPS native subrs Gerd Möllmann
2024-06-25 20:48 ` Gerd Möllmann
2024-06-26 6:31 ` Helmut Eller
2024-06-26 7:00 ` Gerd Möllmann
2024-06-26 13:45 ` Eli Zaretskii
2024-06-26 14:18 ` Gerd Möllmann
2024-06-26 15:15 ` Helmut Eller
2024-06-26 17:12 ` Gerd Möllmann
2024-06-26 13:30 ` Eli Zaretskii
2024-06-26 13:34 ` Eli Zaretskii
2024-06-26 4:55 ` Gerd Möllmann
2024-06-26 13:36 ` Eli Zaretskii
2024-06-26 13:26 ` MPS native subrs (was: MPS make-thread) Eli Zaretskii
2024-06-26 14:41 ` MPS native subrs Andrea Corallo
2024-06-21 12:43 ` MPS: profiler Gerd Möllmann
2024-06-21 16:11 ` Ihor Radchenko
2024-06-21 12:41 ` Gerd Möllmann
2024-06-21 14:10 ` Eli Zaretskii
2024-06-21 16:09 ` Ihor Radchenko
2024-06-21 16:22 ` Gerd Möllmann
2024-06-21 18:51 ` Ihor Radchenko
2024-06-21 18:58 ` Gerd Möllmann
2024-06-21 19:23 ` Ihor Radchenko
2024-06-21 19:50 ` Gerd Möllmann
2024-06-21 20:02 ` Ihor Radchenko
2024-06-22 6:37 ` Eli Zaretskii
2024-06-21 7:43 ` Gerd Möllmann
2024-06-21 7:50 ` Ihor Radchenko
2024-06-21 7:53 ` Gerd Möllmann
2024-06-21 10:39 ` Eli Zaretskii
2024-06-21 10:57 ` Ihor Radchenko
2024-06-21 10:58 ` Eli Zaretskii
2024-06-21 11:20 ` Ihor Radchenko
2024-06-21 11:29 ` Eli Zaretskii
2024-06-21 11:33 ` Gerd Möllmann
2024-06-21 19:55 ` Dmitry Gutov
2024-06-21 16:12 ` Ihor Radchenko
2024-06-21 18:48 ` Eli Zaretskii
2024-06-21 10:49 ` Pip Cet
2024-06-21 10:56 ` Eli Zaretskii
2024-06-21 5:56 ` Eli Zaretskii
2024-06-21 6:14 ` Ihor Radchenko
2024-06-20 19:50 ` Gerd Möllmann
2024-06-20 20:02 ` Ihor Radchenko
2024-06-21 5:58 ` Eli Zaretskii
2024-06-21 6:16 ` Ihor Radchenko
2024-06-21 8:23 ` Pip Cet
2024-06-21 8:43 ` Ihor Radchenko
2024-06-21 8:50 ` Gerd Möllmann
2024-06-21 10:43 ` Eli Zaretskii
2024-06-21 11:00 ` Pip Cet
2024-06-21 11:09 ` Eli Zaretskii
2024-06-21 11:39 ` Gerd Möllmann
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