lkml.org 
[lkml]   [2022]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 2/3] drivers/perf: add DesignWare PCIe PMU driver
On Tue, 27 Sep 2022 13:13:29 +0800
Shuai Xue <xueshuai@linux.alibaba.com> wrote:

> 在 2022/9/27 AM1:18, Bjorn Helgaas 写道:
> > On Mon, Sep 26, 2022 at 09:31:34PM +0800, Shuai Xue wrote:
> >> 在 2022/9/23 PM11:54, Jonathan Cameron 写道:
> >>>> I found a similar definition in arch/ia64/pci/pci.c .
> >>>>
> >>>> #define PCI_SAL_ADDRESS(seg, bus, devfn, reg) \
> >>>> (((u64) seg << 24) | (bus << 16) | (devfn << 8) | (reg))
> >>>>
> >>>> Should we move it into a common header first?
> >>>
> >>> Maybe. The bus, devfn, reg part is standard bdf, but I don't think
> >>> the PCI 6.0 spec defined a version with the seg in the upper bits.
> >>> I'm not sure if we want to adopt that in LInux.
> >>
> >> I found lots of code use seg,bus,devfn,reg with format "%04x:%02x:%02x.%x",
> >> I am not quite familiar with PCIe spec. What do you think about it, Bjorn?
> >
> > The PCIe spec defines an address encoding for bus/device/function/reg
> > for the purposes of ECAM (PCIe r6.0, sec 7.2.2), but as far as I know,
> > it doesn't define anything similar that includes the segment. The
> > segment is really outside the scope of PCIe because each segment is a
> > completely separate PCIe hierarchy.
>
> Thank you for your explanation.
>
> >
> > So I probably wouldn't make this a generic definition. But if/when
> > you print things like this out, please do use the format spec you
> > mentioned above so it matches the style used elsewhere.
> >
>
> Agree. The print format of bus/device/function/reg is "%04x:%02x:%02x.%x",
> so I named the PMU as the same format. Then the usage flow would be:
>
> - lspci to get the device root port in format seg/bus/device/function/reg.
> 10:00.0 PCI bridge: Device 1ded:8000 (rev 01)
> - select its PMU name pcie_bdf_100000.
> - monitor with perf:
> perf stat -a -e pcie_bdf_200/Rx_PCIe_TLP_Data_Payload/

I think you probably want something in there to indicate it's an RP
and the bdf part may be redundant...

Jonathan
>
> Bjorn and Jonathan, are you happy with this flow?
>
> Thank you.
>
> Best Regards,
> Shuai
>

\
 
 \ /
  Last update: 2022-09-27 12:05    [W:0.049 / U:0.204 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site