search for: tun_can_build_skb

...t;> For some reason zerocopy was not applied for most packets, so in most >> cases driver XDP was used. I was going to dig into it but not yet. > > Right, just to confirm this. This is expected. > > In tuntap, we do native XDP only for small and non zerocopy packets. See > tun_can_build_skb(). The reason is XDP may adjust packet header which is > not supported by zercopy. We can only use XDP generic for zerocopy in > this case. I think I understand when driver XDP can be used. What I'm not sure and was going to narrow down is why zerocopy is mostly not applied. -- Toshiak...

...t;> For some reason zerocopy was not applied for most packets, so in most >> cases driver XDP was used. I was going to dig into it but not yet. > > Right, just to confirm this. This is expected. > > In tuntap, we do native XDP only for small and non zerocopy packets. See > tun_can_build_skb(). The reason is XDP may adjust packet header which is > not supported by zercopy. We can only use XDP generic for zerocopy in > this case. I think I understand when driver XDP can be used. What I'm not sure and was going to narrow down is why zerocopy is mostly not applied. -- Toshiak...

...as not applied for most packets, so in most >>>> cases driver XDP was used. I was going to dig into it but not yet. >>> Right, just to confirm this. This is expected. >>> >>> In tuntap, we do native XDP only for small and non zerocopy packets. See >>> tun_can_build_skb(). The reason is XDP may adjust packet header which is >>> not supported by zercopy. We can only use XDP generic for zerocopy in >>> this case. >> I think I understand when driver XDP can be used. What I'm not sure and >> was going to narrow down is why zerocopy is...

...as not applied for most packets, so in most >>>> cases driver XDP was used. I was going to dig into it but not yet. >>> Right, just to confirm this. This is expected. >>> >>> In tuntap, we do native XDP only for small and non zerocopy packets. See >>> tun_can_build_skb(). The reason is XDP may adjust packet header which is >>> not supported by zercopy. We can only use XDP generic for zerocopy in >>> this case. >> I think I understand when driver XDP can be used. What I'm not sure and >> was going to narrow down is why zerocopy is...

...gt;> cases driver XDP was used. I was going to dig into it but not yet. >>>>> Right, just to confirm this. This is expected. >>>>> >>>>> In tuntap, we do native XDP only for small and non zerocopy >>>>> packets. See >>>>> tun_can_build_skb(). The reason is XDP may adjust packet header >>>>> which is >>>>> not supported by zercopy. We can only use XDP generic for zerocopy in >>>>> this case. >>>> I think I understand when driver XDP can be used. What I'm not sure and >&gt...

...+++++++++++++++++++------------------- > 1 file changed, 51 insertions(+), 33 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 389aa0727cc6..21b125020b3b 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, > return true; > } > > +static u32 tun_do_xdp(struct tun_struct *tun, > + struct tun_file *tfile, > + struct bpf_prog *xdp_prog, > + struct xdp_buff *xdp, > + int *err) > +{ > + u32 act =...

...+++++++++++++++++++------------------- > 1 file changed, 51 insertions(+), 33 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 389aa0727cc6..21b125020b3b 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, > return true; > } > > +static u32 tun_do_xdp(struct tun_struct *tun, > + struct tun_file *tfile, > + struct bpf_prog *xdp_prog, > + struct xdp_buff *xdp, > + int *err) > +{ > + u32 act =...

...me reason zerocopy was not applied for most packets, so in most >>> cases driver XDP was used. I was going to dig into it but not yet. >> Right, just to confirm this. This is expected. >> >> In tuntap, we do native XDP only for small and non zerocopy packets. See >> tun_can_build_skb(). The reason is XDP may adjust packet header which is >> not supported by zercopy. We can only use XDP generic for zerocopy in >> this case. > I think I understand when driver XDP can be used. What I'm not sure and > was going to narrow down is why zerocopy is mostly not appl...

...- drivers/net/tun.c | 84 ++++++++++++++++++++++++++++------------------- 1 file changed, 51 insertions(+), 33 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 389aa0727cc6..21b125020b3b 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, return true; } +static u32 tun_do_xdp(struct tun_struct *tun, + struct tun_file *tfile, + struct bpf_prog *xdp_prog, + struct xdp_buff *xdp, + int *err) +{ + u32 act = bpf_prog_run_xdp(xdp_prog, xdp); + + switch (act)...

...ost packets, so in most >>>>> cases driver XDP was used. I was going to dig into it but not yet. >>>> Right, just to confirm this. This is expected. >>>> >>>> In tuntap, we do native XDP only for small and non zerocopy packets. See >>>> tun_can_build_skb(). The reason is XDP may adjust packet header which is >>>> not supported by zercopy. We can only use XDP generic for zerocopy in >>>> this case. >>> I think I understand when driver XDP can be used. What I'm not sure and >>> was going to narrow down is...

...---------- >> 1 file changed, 51 insertions(+), 33 deletions(-) >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index 389aa0727cc6..21b125020b3b 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, >> return true; >> } >> >> +static u32 tun_do_xdp(struct tun_struct *tun, >> + struct tun_file *tfile, >> + struct bpf_prog *xdp_prog, >> + struct xdp_buff *xdp, >> +...

Hi Jason, On 2018/06/29 18:30, Jason Wang wrote: > On 2018?06?29? 16:09, Toshiaki Makita wrote: ... >> To fix this, poll the work instead of enabling notification when >> busypoll is interrupted by something. IMHO signal_pending() and >> vhost_has_work() are kind of interruptions rather than signals to >> completely cancel the busypoll, so let's run busypoll after

Hi Jason, On 2018/06/29 18:30, Jason Wang wrote: > On 2018?06?29? 16:09, Toshiaki Makita wrote: ... >> To fix this, poll the work instead of enabling notification when >> busypoll is interrupted by something. IMHO signal_pending() and >> vhost_has_work() are kind of interruptions rather than signals to >> completely cancel the busypoll, so let's run busypoll after

...use the generic XDP datapath? > For some reason zerocopy was not applied for most packets, so in most > cases driver XDP was used. I was going to dig into it but not yet. Right, just to confirm this. This is expected. In tuntap, we do native XDP only for small and non zerocopy packets. See tun_can_build_skb(). The reason is XDP may adjust packet header which is not supported by zercopy. We can only use XDP generic for zerocopy in this case. > >>> - Set 10us busypoll. >>> - Guest disables checksum and TSO because of host XDP. >>> - Measured single flow Mbps by netperf,...

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

Hi all: This series tries to batch submitting packets to underlayer socket through msg_control during sendmsg(). This is done by: 1) Doing userspace copy inside vhost_net 2) Build XDP buff 3) Batch at most 64 (VHOST_NET_BATCH) XDP buffs and submit them once through msg_control during sendmsg(). 4) Underlayer sockets can use XDP buffs directly when XDP is enalbed, or build skb based on XDP

Hi all: We do not support XDP batching for TUN since it can only receive one packet a time from vhost_net. This series tries to remove this limitation by: - introduce a TUN specific msg_control that can hold a pointer to an array of XDP buffs - try copy and build XDP buff in vhost_net - store XDP buffs in an array and submit them once for every N packets from vhost_net - since TUN can only