On Fri, Jun 09, 2023 at 08:10:22PM +0200, Jan Klemkow wrote:
> On Fri, Jun 09, 2023 at 06:59:57PM +0200, Jan Klemkow wrote:
> > On Fri, Jun 09, 2023 at 06:11:38PM +0200, Jan Klemkow wrote:
> > > TSO packets are limited to MAXMCLBYTES (64k). Thus, we don't need to
> > > allocate IXGBE_TSO_SIZE (256k) per packet for the transmit buffers.
> > >
> > > This saves 3/4 of the memory and allows me to pack over 8 ix(8) ports
> > > into one machine. Otherwise I run out of devbuf in malloc(9).
> >
> > fix typo in comment
>
> Use a more precise compare in the CTASSERT condition.
>
> ok?
I did run this through my performance tests. No difference visible.
OK bluhm@
> Index: dev/pci/if_ix.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/if_ix.c,v
> retrieving revision 1.197
> diff -u -p -r1.197 if_ix.c
> --- dev/pci/if_ix.c 1 Jun 2023 09:05:33 -0000 1.197
> +++ dev/pci/if_ix.c 9 Jun 2023 16:01:18 -0000
> @@ -37,6 +37,12 @@
> #include <dev/pci/if_ix.h>
> #include <dev/pci/ixgbe_type.h>
>
> +/*
> + * Our TCP/IP Stack could not handle packets greater than MAXMCLBYTES.
> + * This interface could not handle packets greater than IXGBE_TSO_SIZE.
> + */
> +CTASSERT(MAXMCLBYTES <= IXGBE_TSO_SIZE);
> +
> /*********************************************************************
> * Driver version
> *********************************************************************/
> @@ -2263,7 +2269,7 @@ ixgbe_allocate_transmit_buffers(struct t
> /* Create the descriptor buffer dma maps */
> for (i = 0; i < sc->num_tx_desc; i++) {
> txbuf = &txr->tx_buffers[i];
> - error = bus_dmamap_create(txr->txdma.dma_tag, IXGBE_TSO_SIZE,
> + error = bus_dmamap_create(txr->txdma.dma_tag, MAXMCLBYTES,
> sc->num_segs, PAGE_SIZE, 0,
> BUS_DMA_NOWAIT, &txbuf->map);
>
