On Mon, Jan 28, 2013 at 11:09 PM, Yijing Wang <wangyijing@xxxxxxxxxx> wrote: > On 2013/1/29 13:00, Jon Mason wrote: >> On Fri, Jan 25, 2013 at 2:36 AM, Yijing Wang <wangyijing@xxxxxxxxxx> wrote: >>> v0->v1: Update MPS parameters as non-arch and add MRRS >>> description into pcie_bus_perf parameter suggested >>> by Andrew Murray. >>> v1->v2: Update some semantic problems and add MPS and MRRS >>> explanation suggested by Joe Lawrence and Randy Dunlap. >>> v2->v3: Update some semantic problems and the description >>> of pcie_bus_safe and pcie_bus_peer2peer suggested >>> by Bjorn Helgaas. >>> >>> Document PCIE BUS MPS parameters pcie_bus_tune_off, pcie_bus_safe, >>> pcie_bus_peer2peer, pcie_bus_perf into Documentation/kernel-parameters.txt. >>> These parameters were introduced by Jon Mason <mason@xxxxxxxx> at >>> commit 5f39e6705 and commit b03e7495a8. >>> >>> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx> >>> --- >>> Documentation/kernel-parameters.txt | 13 +++++++++++++ >>> 1 files changed, 13 insertions(+), 0 deletions(-) >>> >>> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt >>> index 363e348..2997df2 100644 >>> --- a/Documentation/kernel-parameters.txt >>> +++ b/Documentation/kernel-parameters.txt >>> @@ -2227,6 +2227,19 @@ bytes respectively. Such letter suffixes can also be entirely omitted. >>> This sorting is done to get a device >>> order compatible with older (<= 2.4) kernels. >>> nobfsort Don't sort PCI devices into breadth-first order. >>> + pcie_bus_tune_off Disable PCIe MPS (Max Payload Size) >>> + tuning and use the BIOS-configured MPS defaults. >>> + pcie_bus_safe Use the smallest supported MPS of any device >>> + below a root complex. >> >> This isn't correct. It should be something like "The largest MPS >> common to all devices below the root complex". > > Hi Jon, > Thanks for your review and comment! > What about "Set every device's MPS to the largest MPSS (Max Payload Size Support) > common to all devices below the root complex" ? Sounds great! Thanks so much for documenting this. > >> >>> + pcie_bus_perf Configure device MPS to the largest >>> + allowable MPS based on its parent bus. Also set >>> + MRRS (Max Read Request Size) to the largest supported >>> + value (no larger than the MPS that the device or bus >>> + can support) for best performance. >>> + pcie_bus_peer2peer Set every device's MPS to 128B, which >>> + every device is guaranteed to support. This >>> + configuration allows peer-to-peer DMA between any pair >>> + of devices possibly at the cost of reduced performance. >>> cbiosize=nn[KMG] The fixed amount of bus space which is >>> reserved for the CardBus bridge's IO window. >>> The default value is 256 bytes. >>> -- >>> 1.7.1 >>> >>> >> >> . >> > > > -- > Thanks! > Yijing > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
