* poison_obj latency
@ 2007-06-27 10:51 Manfred Gruber
2007-06-27 12:34 ` Ingo Molnar
0 siblings, 1 reply; 3+ messages in thread
From: Manfred Gruber @ 2007-06-27 10:51 UTC (permalink / raw)
To: linux-rt-users
hi !
I use a arm4vt ep93xx processor with 2.6.21.5-rt18.
When i run cyclictest with -i 10000 and -n -p 90 -b 1000 i see some strange
latencies in poison_obj.
the output from /proc/latency_trace where the latency is shown:
OLD:cyclicte-884 0.... 13493us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 13830us+: 336us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 13848us+: 18us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 47181us!: 4us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 47514us+: 333us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 47533us+: 18us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 90226us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 90564us+: 338us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 90584us+: 19us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 125182us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 125520us+: 338us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 125540us+: 19us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 157308us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 157644us+: 335us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 157661us+: 17us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0D..1 193339us!: 5us:
trace_stop_sched_switched+0x14/0x374 (__schedule+0x478/0x5a4)
ACT:cyclicte-884 0.... 193662us+: 323us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 193683us+: 21us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 226083us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 226419us+: 335us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 226438us+: 19us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 258101us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 258438us+: 336us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 258456us+: 18us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 290710us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 291047us+: 336us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 291063us+: 16us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
OLD:cyclicte-884 0.... 327645us!: 5us: check_poison_obj+0x14/0x1bc
(cache_alloc_debugcheck_after+0x38/0x160)
ACT:cyclicte-884 0.... 327982us+: 336us: poison_obj+0x10/0x40
(cache_alloc_debugcheck_after+0x48/0x160)
NEW:cyclicte-884 0.... 328002us+: 20us: get_unused_fd+0x10/0xf4
(do_sys_open+0x3c/0xe8)
does someone have an idea where this comes from ?
the hole /proc/latency output is shown here:
https://dev.contec.at/micro9/tmp/l_t.txt
--
regards
Manfred Gruber
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: poison_obj latency
2007-06-27 10:51 poison_obj latency Manfred Gruber
@ 2007-06-27 12:34 ` Ingo Molnar
2007-06-27 13:24 ` Manfred Gruber
0 siblings, 1 reply; 3+ messages in thread
From: Ingo Molnar @ 2007-06-27 12:34 UTC (permalink / raw)
To: Manfred Gruber; +Cc: linux-rt-users
* Manfred Gruber <m.gruber@tirol.com> wrote:
> hi !
>
> I use a arm4vt ep93xx processor with 2.6.21.5-rt18.
> When i run cyclictest with -i 10000 and -n -p 90 -b 1000 i see some strange
> latencies in poison_obj.
disable SLAB_DEBUG. And look into your 'dmesg' output, the -rt kernel
will warn about any other kernel config options as well that are known
to cause large latencies:
VFS: Mounted root (ext3 filesystem) readonly.
*****************************************************************************
* *
* REMINDER, the following debugging option is turned on in your .config: *
* *
* CONFIG_SLAB *
* *
* it may increase runtime overhead and latencies. *
* *
*****************************************************************************
Freeing unused kernel memory: 324k freed
Ingo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: poison_obj latency
2007-06-27 12:34 ` Ingo Molnar
@ 2007-06-27 13:24 ` Manfred Gruber
0 siblings, 0 replies; 3+ messages in thread
From: Manfred Gruber @ 2007-06-27 13:24 UTC (permalink / raw)
To: Ingo Molnar, linux-rt-users
Am Mittwoch, 27. Juni 2007 14:34 schrieben Sie:
> * Manfred Gruber <m.gruber@tirol.com> wrote:
> > hi !
> >
> > I use a arm4vt ep93xx processor with 2.6.21.5-rt18.
> > When i run cyclictest with -i 10000 and -n -p 90 -b 1000 i see some
> > strange latencies in poison_obj.
>
> disable SLAB_DEBUG. And look into your 'dmesg' output, the -rt kernel
> will warn about any other kernel config options as well that are known
> to cause large latencies:
>
> VFS: Mounted root (ext3 filesystem) readonly.
> ***************************************************************************
>** *
> * * REMINDER, the following debugging option is turned on in your
> .config: * *
> * * CONFIG_SLAB
> * *
> * * it may increase runtime overhead and latencies.
> * *
> *
> ***************************************************************************
>** Freeing unused kernel memory: 324k freed
>
> Ingo
ok, thanks without SLAB_DEBUG there is no poison_obj latency.
--
mfg
Manfred Gruber
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-06-27 13:24 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2007-06-27 10:51 poison_obj latency Manfred Gruber
2007-06-27 12:34 ` Ingo Molnar
2007-06-27 13:24 ` Manfred Gruber
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