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From: Logan Gunthorpe <logang@deltatee.com>
To: Bjorn Helgaas <helgaas@kernel.org>,
	Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: Possible PCI Regression Linux 5.3-rc1
Date: Wed, 24 Jul 2019 09:48:19 -0600	[thread overview]
Message-ID: <c016b0b3-6e76-625d-e603-65ddb1286cf6@deltatee.com> (raw)
In-Reply-To: <20190724133814.GA194025@google.com>



On 2019-07-24 7:38 a.m., Bjorn Helgaas wrote:
> On Wed, Jul 24, 2019 at 12:54:00PM +0000, Nicholas Johnson wrote:
>> Hi all,
>>
>> I was just rebasing my patches for linux 5.3-rc1 and noticed a possible 
>> regression that shows on both of my machines. It is also reproducible 
>> with the unmodified Ubuntu mainline kernel, downloadable at [1].
>>
>> Running the lspci command takes 1-3 seconds with 5.3-rc1 (rather than an 
>> imperceivable amount of time). Booting with pci.dyndbg does not reveal 
>> why.
>>
>> $ uname -r
>> 5.3.0-050300rc1-generic
>> $ time lspci -vt 1>/dev/null
>>
>> real	0m2.321s
>> user	0m0.026s
>> sys	0m0.000s
>>
>> If none of you are aware of this or what is causing it, I will submit a 
>> bug report to Bugzilla.
> 
> I wasn't aware of this; thanks for reporting it!  I wasn't able to
> reproduce this in qemu.  Can you play with "strace -r lspci -vt" and
> the like?  Maybe try "lspci -n" to see if it's related to looking up
> the names?
I also just tested 5.3-rc1 on my machine and lspci behaves normally.

Logan

  reply	other threads:[~2019-07-24 15:48 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-24 12:54 Possible PCI Regression Linux 5.3-rc1 Nicholas Johnson
2019-07-24 13:38 ` Bjorn Helgaas
2019-07-24 15:48   ` Logan Gunthorpe [this message]
2019-07-25 13:21     ` Nicholas Johnson
2019-07-25 13:18   ` Nicholas Johnson
2019-07-25 15:50     ` Logan Gunthorpe
2019-08-04  8:47       ` Nicholas Johnson
2019-08-05  8:59         ` Nicholas Johnson
2019-08-05 12:34         ` Mika Westerberg
2019-08-05 14:09           ` Nicholas Johnson
2019-08-05 14:25           ` Nicholas Johnson

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