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    Subject[RFC PATCH v3 3/7] proc: Reduce cache miss in snmp6_seq_show
    Date
    This is to use the generic interface snmp_get_cpu_field{,64}_batch to 
    aggregate the data by going through all the items of each cpu sequentially.

    Signed-off-by: Jia He <hejianet@gmail.com>
    ---
    net/ipv6/proc.c | 32 +++++++++++++++++++++++---------
    1 file changed, 23 insertions(+), 9 deletions(-)

    diff --git a/net/ipv6/proc.c b/net/ipv6/proc.c
    index 679253d0..50ba2c3 100644
    --- a/net/ipv6/proc.c
    +++ b/net/ipv6/proc.c
    @@ -30,6 +30,11 @@
    #include <net/transp_v6.h>
    #include <net/ipv6.h>

    +#define MAX4(a, b, c, d) \
    + max_t(u32, max_t(u32, a, b), max_t(u32, c, d))
    +#define SNMP_MIB_MAX MAX4(UDP_MIB_MAX, TCP_MIB_MAX, \
    + IPSTATS_MIB_MAX, ICMP_MIB_MAX)
    +
    static int sockstat6_seq_show(struct seq_file *seq, void *v)
    {
    struct net *net = seq->private;
    @@ -192,13 +197,19 @@ static void snmp6_seq_show_item(struct seq_file *seq, void __percpu *pcpumib,
    const struct snmp_mib *itemlist)
    {
    int i;
    - unsigned long val;
    -
    - for (i = 0; itemlist[i].name; i++) {
    - val = pcpumib ?
    - snmp_fold_field(pcpumib, itemlist[i].entry) :
    - atomic_long_read(smib + itemlist[i].entry);
    - seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name, val);
    + unsigned long buff[SNMP_MIB_MAX];
    +
    + memset(buff, 0, sizeof(unsigned long) * SNMP_MIB_MAX);
    +
    + if (pcpumib) {
    + snmp_get_cpu_field_batch(buff, itemlist, pcpumib);
    + for (i = 0; itemlist[i].name; i++)
    + seq_printf(seq, "%-32s\t%lu\n",
    + itemlist[i].name, buff[i]);
    + } else {
    + for (i = 0; itemlist[i].name; i++)
    + seq_printf(seq, "%-32s\t%lu\n", itemlist[i].name,
    + atomic_long_read(smib + itemlist[i].entry));
    }
    }

    @@ -206,10 +217,13 @@ static void snmp6_seq_show_item64(struct seq_file *seq, void __percpu *mib,
    const struct snmp_mib *itemlist, size_t syncpoff)
    {
    int i;
    + u64 buff64[SNMP_MIB_MAX];
    +
    + memset(buff64, 0, sizeof(unsigned long) * SNMP_MIB_MAX);

    + snmp_get_cpu_field64_batch(buff64, itemlist, mib, syncpoff);
    for (i = 0; itemlist[i].name; i++)
    - seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name,
    - snmp_fold_field64(mib, itemlist[i].entry, syncpoff));
    + seq_printf(seq, "%-32s\t%llu\n", itemlist[i].name, buff64[i]);
    }

    static int snmp6_seq_show(struct seq_file *seq, void *v)
    --
    1.8.3.1
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      Last update: 2016-09-17 09:58    [W:3.514 / U:0.108 seconds]
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