On Wed, Dec 7, 2016 at 4:41 AM, Andrew Lunn <and...@lunn.ch> wrote: > On Wed, Dec 07, 2016 at 12:33:08AM +0200, Saeed Mahameed wrote: >> Hi Dave, >> >> This series adds the support for setting device registers from user >> space ethtool. > > Is this not the start of allowing binary only drivers in user space? >
It is not, we want to do same as set_eeprom already do, Just set some HW registers, for analysis/debug/tweak/configure HW dependent register for the NIC netdev sake. > Do we want this? > Apparently yes, Our performance team will be happy to have such feature upstream, so they can just jump in and start their performance analysis/debugging with ethtool directly without the need of extra proprietary FW tools (which sometimes demand reboot and driver restart for each configuration). This is one usage and i believe other NIC vendors will be happy to have this. > >> mlx5 driver have registers allowed access list and will check the user >> Request validity before forwarding it to HW registers. Mlx5 will allow only >> mlx5 specific >> configurations to be set (e.g. Device Diag Counters for HW performance >> debugging and analysis) >> which has no standard API to access it. > > Would it not be better to define an flexible API to do this? We have > lots of HW performance counters for CPUs. Why is it not possible to do > this for a network device? > What is flexible in this context ? Register Types/layout and purposes differs from vendor to vendor and changes cross HW updates and new HW generations. We simply don't want to inform/update the stack and ethtool API about each register layout, this is just not scalable, and those registers are not precisely meant for performance/debug counters, sometimes they have some other purposes. For example configuring an internal HW unit to work in different ways, so we can have some taste of "on the fly" control for testing purposes. where can i find some details about "HW performance counters for CPUs" ? In light of my response, if you have any suggestion for more flexible (strongly typed) API, I will be glad to hear about it. Thanks for your response. Saeed.
