From: pavel <pavel@pavlinux.ru>
To: Clark Williams <williams@redhat.com>
Cc: Linux RT Users <linux-rt-users@vger.kernel.org>
Subject: Re: 1us latency?
Date: Mon, 3 Aug 2015 20:59:56 +0300 [thread overview]
Message-ID: <55BFAC1C.9020508@pavlinux.ru> (raw)
In-Reply-To: <20150803114422.0efbea1b@sluggy>
03.08.2015 19:44, Clark Williams пишет:
> On Mon, 3 Aug 2015 14:13:27 +0300
> pavel <pavel@pavlinux.ru> wrote:
>
>> # ./cyclictest -S -p fifo
>> defaulting realtime priority to 9
>> # /dev/cpu_dma_latency set to 0us
>> policy: fifo: loadavg: 0.00 0.03 0.05 1/218 4240
>>
>> T: 0 ( 4174) P: 9 I:1000 C: 430806 Min: 1 Act: 1 Avg: 1 Max: 10
>> T: 1 ( 4175) P: 9 I:1500 C: 287204 Min: 1 Act: 1 Avg: 1 Max: 6
>> T: 2 ( 4176) P: 9 I:2000 C: 215403 Min: 1 Act: 2 Avg: 1 Max: 11
>> T: 3 ( 4177) P: 9 I:2500 C: 172322 Min: 1 Act: 1 Avg: 1 Max: 9
>> T: 4 ( 4178) P: 9 I:3000 C: 143602 Min: 1 Act: 1 Avg: 1 Max: 10
>> T: 5 ( 4179) P: 9 I:3500 C: 123087 Min: 1 Act: 1 Avg: 1 Max: 11
>> T: 6 ( 4180) P: 9 I:4000 C: 107701 Min: 1 Act: 1 Avg: 1 Max: 10
>> T: 7 ( 4181) P: 9 I:4500 C: 108232 Min: 1 Act: 2 Avg: 1 Max: 11
>>
>>
>> It possible? 1us latency? o_O
>>
>> kernel- 3.18.19-rt15
>> cyclictest V 0.92
>> Intel(R) Xeon(R) CPU E3-1246 v3 @ 3.50GHz
>> MSI MS-7823/B85M-G43 (MS-7823), BIOS V3.14B3 06/23/2014
>> --
> No, your latency is 11us. Max latency is what we care about, not the
> average.
By the way, max values appear only at the start, then they are roughly equal to
the average.
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next prev parent reply other threads:[~2015-08-03 18:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-03 11:13 1us latency? pavel
2015-08-03 16:44 ` Clark Williams
2015-08-03 17:59 ` pavel [this message]
2015-08-03 18:36 ` pavel
2015-08-03 18:53 ` Clark Williams
2015-08-03 19:03 ` pavel
2015-08-04 20:27 ` Frank Rowand
2015-08-06 13:12 ` Sebastian Andrzej Siewior
2015-08-06 15:03 ` Clark Williams
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