On 12/02/2016 11:21 AM, Grygorii Strashko wrote: > > > On 12/02/2016 05:28 AM, Ivan Khoronzhuk wrote: >> On Thu, Dec 01, 2016 at 05:34:30PM -0600, Grygorii Strashko wrote: >>> Add optional property "descs_pool_size" to specify buffer descriptor's >>> pool size. The "descs_pool_size" should define total number of CPDMA >>> CPPI descriptors to be used for both ingress/egress packets >>> processing. If not specified - the default value 256 will be used >>> which will allow to place descriptor's pool into the internal CPPI >>> RAM on most of TI SoC. >>> >>> Signed-off-by: Grygorii Strashko <grygorii.stras...@ti.com> >>> --- >>> Documentation/devicetree/bindings/net/cpsw.txt | 5 +++++ >>> 1 file changed, 5 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/net/cpsw.txt >>> b/Documentation/devicetree/bindings/net/cpsw.txt >>> index 5ad439f..b99d196 100644 >>> --- a/Documentation/devicetree/bindings/net/cpsw.txt >>> +++ b/Documentation/devicetree/bindings/net/cpsw.txt >>> @@ -35,6 +35,11 @@ Optional properties: >>> For example in dra72x-evm, pcf gpio has to be >>> driven low so that cpsw slave 0 and phy data >>> lines are connected via mux. >>> +- descs_pool_size : total number of CPDMA CPPI descriptors to be used for >>> + both ingress/egress packets processing. if not >>> + specified the default value 256 will be used which >>> + will allow to place descriptors pool into the >>> + internal CPPI RAM. >> Does it describe h/w? Why now module parameter? or even smth like ethtool num >> ring entries? >> > > It can be module parameter too. for the use cases i'm aware of - > this is one-time boot setting only. > > ----- OR > So, do you propose to use > ethtool -g ethX > > ethtool -G ethX [rx N] [tx N] > ? > > Now cpdma has one pool for all RX/TX channels, so changing this settings > by ethtool will require: pause interfaces, reallocate cpdma pool, > re-arrange buffers between channels, resume interface. Correct? > > How do you think - we can move forward with one pool or better to have two > (Rx and Tx)? > > Wouldn't it be reasonable to still have DT (or module) parameter to avoid > cpdma reconfiguration on system startup (pause/resume interfaces) (faster > boot)? > > How about cpdma re-allocation policy (with expectation that is shouldn't > happen too often)? > - increasing of Rx, Tx will grow total number of physically allocated buffers > (total_desc_num) > - decreasing of Rx, Tx will just change number of available buffers (no > memory re-allocation) > > ----- OR ---- > Can we move forward with current patch (total number of CPDMA CPPI > descriptors defined in DT) > and add ethtool -G ethX [rx N] [tx N] which will allow to re-split descs > between RX and TX? > >
if no comments here, I'll rework patches to use module parameter for descs_pool_size and will add possibility to re-split RX/TX buffers using ethtool -G ethX [rx N] [tx N] -- regards, -grygorii
