| Message ID | 20180713161841.11202-4-gregory.clement@bootlin.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | A fix and a few improvements on mvneta | expand |
On Fri, Jul 13, 2018 at 06:18:37PM +0200, Gregory CLEMENT wrote: > From: Yelena Krivosheev <yelena@marvell.com> > > The initial values were too small leading to poor performance when using > the software buffer management. What does this do to latency when a large transfer is also ongoing (iow, the classic bufferbloat issue) ? > > Signed-off-by: Yelena Krivosheev <yelena@marvell.com> > [gregory: extract from a larger patch] > Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> > --- > drivers/net/ethernet/marvell/mvneta.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c > index f4e3943a745d..c22df28b07c8 100644 > --- a/drivers/net/ethernet/marvell/mvneta.c > +++ b/drivers/net/ethernet/marvell/mvneta.c > @@ -295,10 +295,10 @@ > #define MVNETA_RSS_LU_TABLE_SIZE 1 > > /* Max number of Rx descriptors */ > -#define MVNETA_MAX_RXD 128 > +#define MVNETA_MAX_RXD 512 > > /* Max number of Tx descriptors */ > -#define MVNETA_MAX_TXD 532 > +#define MVNETA_MAX_TXD 1024 > > /* Max number of allowed TCP segments for software TSO */ > #define MVNETA_MAX_TSO_SEGS 100 > -- > 2.18.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Hi Russell King, On ven., juil. 13 2018, Russell King - ARM Linux <linux@armlinux.org.uk> wrote: > On Fri, Jul 13, 2018 at 06:18:37PM +0200, Gregory CLEMENT wrote: >> From: Yelena Krivosheev <yelena@marvell.com> >> >> The initial values were too small leading to poor performance when using >> the software buffer management. > > What does this do to latency when a large transfer is also ongoing > (iow, the classic bufferbloat issue) ? IXIA latency test had been done without seeing any differences for long traffic (routing). These new values offer better performance for the main usage of this SoC (NAS applications), however both Rx and TX queues size can be change by ethtool. Gregory > >> >> Signed-off-by: Yelena Krivosheev <yelena@marvell.com> >> [gregory: extract from a larger patch] >> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> >> --- >> drivers/net/ethernet/marvell/mvneta.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c >> index f4e3943a745d..c22df28b07c8 100644 >> --- a/drivers/net/ethernet/marvell/mvneta.c >> +++ b/drivers/net/ethernet/marvell/mvneta.c >> @@ -295,10 +295,10 @@ >> #define MVNETA_RSS_LU_TABLE_SIZE 1 >> >> /* Max number of Rx descriptors */ >> -#define MVNETA_MAX_RXD 128 >> +#define MVNETA_MAX_RXD 512 >> >> /* Max number of Tx descriptors */ >> -#define MVNETA_MAX_TXD 532 >> +#define MVNETA_MAX_TXD 1024 >> >> /* Max number of allowed TCP segments for software TSO */ >> #define MVNETA_MAX_TSO_SEGS 100 >> -- >> 2.18.0 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > -- > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up > According to speedtest.net: 13Mbps down 490kbps up
On Wed, Jul 18, 2018 at 8:39 AM Gregory CLEMENT <gregory.clement@bootlin.com> wrote: > > Hi Russell King, > > On ven., juil. 13 2018, Russell King - ARM Linux <linux@armlinux.org.uk> wrote: > > > On Fri, Jul 13, 2018 at 06:18:37PM +0200, Gregory CLEMENT wrote: > >> From: Yelena Krivosheev <yelena@marvell.com> > >> > >> The initial values were too small leading to poor performance when using > >> the software buffer management. > > > > What does this do to latency when a large transfer is also ongoing > > (iow, the classic bufferbloat issue) ? > > IXIA latency test had been done without seeing any differences for long > traffic (routing). IXIA's tests in the latency under load area are pure rubbish. try irtt, netperf, + flent (which wraps those) https://github.com/heistp/irtt - with good one way delay measurements, has been coming along nicely of late. > These new values offer better performance for the main usage of this SoC > (NAS applications), however both Rx and TX queues size can be change by > ethtool. BQL was added to this driver as of commit a29b6235560a1ed10c8e1a73bfc616a66b802b90, with typical latencies below 2ms range. Is that not still the case? at a gbit, 1500 byte packets, non-gso, that's a ring buffer size of ~155. So I can imagine that your proposed larger ring buffer size for smaller packets might help, (was your test using smaller packets?) and the usage of BQL should obscure any change of latency seen by increasing the limit. (in other words, assuming bql is working, go right ahead, increase tx descriptors) bqlmon can be used to monitor the state of bql. as for rx, are you seeing drops under load due to overflowing it? When I last looked at this driver (in the pre-bql era), it did a lot of bulky processing in rx. > > Gregory > > > > >> > >> Signed-off-by: Yelena Krivosheev <yelena@marvell.com> > >> [gregory: extract from a larger patch] > >> Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com> > >> --- > >> drivers/net/ethernet/marvell/mvneta.c | 4 ++-- > >> 1 file changed, 2 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c > >> index f4e3943a745d..c22df28b07c8 100644 > >> --- a/drivers/net/ethernet/marvell/mvneta.c > >> +++ b/drivers/net/ethernet/marvell/mvneta.c > >> @@ -295,10 +295,10 @@ > >> #define MVNETA_RSS_LU_TABLE_SIZE 1 > >> > >> /* Max number of Rx descriptors */ > >> -#define MVNETA_MAX_RXD 128 > >> +#define MVNETA_MAX_RXD 512 > >> > >> /* Max number of Tx descriptors */ > >> -#define MVNETA_MAX_TXD 532 > >> +#define MVNETA_MAX_TXD 1024 > >> > >> /* Max number of allowed TCP segments for software TSO */ > >> #define MVNETA_MAX_TSO_SEGS 100 > >> -- > >> 2.18.0 > >> > >> > >> _______________________________________________ > >> linux-arm-kernel mailing list > >> linux-arm-kernel@lists.infradead.org > >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > > > -- > > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ > > FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up > > According to speedtest.net: 13Mbps down 490kbps up > > -- > Gregory Clement, Bootlin (formerly Free Electrons) > Embedded Linux and Kernel engineering > http://bootlin.com
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c index f4e3943a745d..c22df28b07c8 100644 --- a/drivers/net/ethernet/marvell/mvneta.c +++ b/drivers/net/ethernet/marvell/mvneta.c @@ -295,10 +295,10 @@ #define MVNETA_RSS_LU_TABLE_SIZE 1 /* Max number of Rx descriptors */ -#define MVNETA_MAX_RXD 128 +#define MVNETA_MAX_RXD 512 /* Max number of Tx descriptors */ -#define MVNETA_MAX_TXD 532 +#define MVNETA_MAX_TXD 1024 /* Max number of allowed TCP segments for software TSO */ #define MVNETA_MAX_TSO_SEGS 100