linux/net/core/timestamping.c
Eric Dumazet 93aaae2e01 filter: optimize sk_run_filter
Remove pc variable to avoid arithmetic to compute fentry at each filter
instruction. Jumps directly manipulate fentry pointer.

As the last instruction of filter[] is guaranteed to be a RETURN, and
all jumps are before the last instruction, we dont need to check filter
bounds (number of instructions in filter array) at each iteration, so we
remove it from sk_run_filter() params.

On x86_32 remove f_k var introduced in commit 57fe93b374
(filter: make sure filters dont read uninitialized memory)

Note : We could use a CONFIG_ARCH_HAS_{FEW|MANY}_REGISTERS in order to
avoid too many ifdefs in this code.

This helps compiler to use cpu registers to hold fentry and A
accumulator.

On x86_32, this saves 401 bytes, and more important, sk_run_filter()
runs much faster because less register pressure (One less conditional
branch per BPF instruction)

# size net/core/filter.o net/core/filter_pre.o
   text    data     bss     dec     hex filename
   2948       0       0    2948     b84 net/core/filter.o
   3349       0       0    3349     d15 net/core/filter_pre.o

on x86_64 :
# size net/core/filter.o net/core/filter_pre.o
   text    data     bss     dec     hex filename
   5173       0       0    5173    1435 net/core/filter.o
   5224       0       0    5224    1468 net/core/filter_pre.o

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-11-19 09:49:59 -08:00

127 lines
2.9 KiB
C

/*
* PTP 1588 clock support - support for timestamping in PHY devices
*
* Copyright (C) 2010 OMICRON electronics GmbH
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/errqueue.h>
#include <linux/phy.h>
#include <linux/ptp_classify.h>
#include <linux/skbuff.h>
static struct sock_filter ptp_filter[] = {
PTP_FILTER
};
static unsigned int classify(struct sk_buff *skb)
{
if (likely(skb->dev &&
skb->dev->phydev &&
skb->dev->phydev->drv))
return sk_run_filter(skb, ptp_filter);
else
return PTP_CLASS_NONE;
}
void skb_clone_tx_timestamp(struct sk_buff *skb)
{
struct phy_device *phydev;
struct sk_buff *clone;
struct sock *sk = skb->sk;
unsigned int type;
if (!sk)
return;
type = classify(skb);
switch (type) {
case PTP_CLASS_V1_IPV4:
case PTP_CLASS_V1_IPV6:
case PTP_CLASS_V2_IPV4:
case PTP_CLASS_V2_IPV6:
case PTP_CLASS_V2_L2:
case PTP_CLASS_V2_VLAN:
phydev = skb->dev->phydev;
if (likely(phydev->drv->txtstamp)) {
clone = skb_clone(skb, GFP_ATOMIC);
if (!clone)
return;
clone->sk = sk;
phydev->drv->txtstamp(phydev, clone, type);
}
break;
default:
break;
}
}
void skb_complete_tx_timestamp(struct sk_buff *skb,
struct skb_shared_hwtstamps *hwtstamps)
{
struct sock *sk = skb->sk;
struct sock_exterr_skb *serr;
int err;
if (!hwtstamps)
return;
*skb_hwtstamps(skb) = *hwtstamps;
serr = SKB_EXT_ERR(skb);
memset(serr, 0, sizeof(*serr));
serr->ee.ee_errno = ENOMSG;
serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
skb->sk = NULL;
err = sock_queue_err_skb(sk, skb);
if (err)
kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
bool skb_defer_rx_timestamp(struct sk_buff *skb)
{
struct phy_device *phydev;
unsigned int type;
skb_push(skb, ETH_HLEN);
type = classify(skb);
skb_pull(skb, ETH_HLEN);
switch (type) {
case PTP_CLASS_V1_IPV4:
case PTP_CLASS_V1_IPV6:
case PTP_CLASS_V2_IPV4:
case PTP_CLASS_V2_IPV6:
case PTP_CLASS_V2_L2:
case PTP_CLASS_V2_VLAN:
phydev = skb->dev->phydev;
if (likely(phydev->drv->rxtstamp))
return phydev->drv->rxtstamp(phydev, skb, type);
break;
default:
break;
}
return false;
}
void __init skb_timestamping_init(void)
{
BUG_ON(sk_chk_filter(ptp_filter, ARRAY_SIZE(ptp_filter)));
}