Re: [Qemu-devel] [RFC PATCH V5 3/4] colo-compare: introduce packet comparison thread

[Zhang Chen <zhangchen.fnst@cn.fujitsu.com>]

On 07/08/2016 12:23 PM, Jason Wang wrote:
>
>
> On 2016年06月23日 19:34, Zhang Chen wrote:
>> if packets are same, we send primary packet and drop secondary
>> packet, otherwise notify COLO do checkpoint.
>
> More verbose please, e.g how to handle each case of exception (or 
> maybe comment in the code).
>

OK.

>>
>> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>> ---
>>   net/colo-base.c    |   1 +
>>   net/colo-base.h    |   3 +
>>   net/colo-compare.c | 214 
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   trace-events       |   2 +
>>   4 files changed, 220 insertions(+)
>>
>> diff --git a/net/colo-base.c b/net/colo-base.c
>> index 7e263e8..9673661 100644
>> --- a/net/colo-base.c
>> +++ b/net/colo-base.c
>> @@ -146,6 +146,7 @@ Packet *packet_new(const void *data, int size)
>>         pkt->data = g_memdup(data, size);
>>       pkt->size = size;
>> +    pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_HOST);
>>         return pkt;
>>   }
>> diff --git a/net/colo-base.h b/net/colo-base.h
>> index 01c1a5d..8bb1043 100644
>> --- a/net/colo-base.h
>> +++ b/net/colo-base.h
>> @@ -18,6 +18,7 @@
>>   #include "slirp/slirp.h"
>>   #include "qemu/jhash.h"
>>   #include "qemu/rcu.h"
>> +#include "qemu/timer.h"
>>     #define HASHTABLE_MAX_SIZE 16384
>>   @@ -47,6 +48,8 @@ typedef struct Packet {
>>       };
>>       uint8_t *transport_layer;
>>       int size;
>> +    /* Time of packet creation, in wall clock ms */
>> +    int64_t creation_ms;
>>   } Packet;
>>     typedef struct ConnectionKey {
>> diff --git a/net/colo-compare.c b/net/colo-compare.c
>> index 4231fe7..928d729 100644
>> --- a/net/colo-compare.c
>> +++ b/net/colo-compare.c
>> @@ -35,6 +35,8 @@
>>       OBJECT_CHECK(CompareState, (obj), TYPE_COLO_COMPARE)
>>     #define COMPARE_READ_LEN_MAX NET_BUFSIZE
>> +/* TODO: Should be configurable */
>> +#define REGULAR_CHECK_MS 400
>
> "REGULAR" seems to generic, need a better name.

Like  "REGULAR_PACKET_CHECK_MS" ?

>
>>     static QTAILQ_HEAD(, CompareState) net_compares =
>>          QTAILQ_HEAD_INITIALIZER(net_compares);
>> @@ -86,6 +88,11 @@ typedef struct CompareState {
>>       GQueue unprocessed_connections;
>>       /* proxy current hash size */
>>       uint32_t hashtable_size;
>> +    /* compare thread, a thread for each NIC */
>> +    QemuThread thread;
>> +    int thread_status;
>> +    /* Timer used on the primary to find packets that are never 
>> matched */
>> +    QEMUTimer *timer;
>>   } CompareState;
>>     typedef struct CompareClass {
>> @@ -97,6 +104,15 @@ enum {
>>       SECONDARY_IN,
>>   };
>>   +enum {
>> +    /* compare thread isn't started */
>> +    COMPARE_THREAD_NONE,
>> +    /* compare thread is running */
>> +    COMPARE_THREAD_RUNNING,
>> +    /* compare thread exit */
>> +    COMPARE_THREAD_EXIT,
>> +};
>> +
>>   static int compare_chr_send(CharDriverState *out,
>>                               const uint8_t *buf,
>>                               uint32_t size);
>> @@ -143,6 +159,98 @@ static int packet_enqueue(CompareState *s, int 
>> mode)
>>       return 0;
>>   }
>>   +/*
>> + * The IP packets sent by primary and secondary
>> + * will be compared in here
>> + * TODO support ip fragment, Out-Of-Order
>> + * return:    0  means packet same
>> + *            > 0 || < 0 means packet different
>> + */
>> +static int colo_packet_compare(Packet *ppkt, Packet *spkt)
>> +{
>> +    trace_colo_compare_ip_info(ppkt->size, inet_ntoa(ppkt->ip->ip_src),
>> + inet_ntoa(ppkt->ip->ip_dst), spkt->size,
>> + inet_ntoa(spkt->ip->ip_src),
>> + inet_ntoa(spkt->ip->ip_dst));
>> +
>> +    if (ppkt->size == spkt->size) {
>> +        return memcmp(ppkt->data, spkt->data, spkt->size);
>> +    } else {
>> +        return -1;
>> +    }
>> +}
>> +
>> +static int colo_packet_compare_all(Packet *spkt, Packet *ppkt)
>> +{
>> +    trace_colo_compare_main("compare all");
>> +    return colo_packet_compare(ppkt, spkt);
>> +}
>> +
>> +static void colo_old_packet_check(void *opaque_packet, void 
>> *opaque_found)
>> +{
>> +    int64_t now;
>> +    bool *found_old = (bool *)opaque_found;
>> +    Packet *ppkt = (Packet *)opaque_packet;
>> +
>> +    if (*found_old) {
>> +        /* Someone found an old packet earlier in the queue */
>> +        return;
>> +    }
>> +
>> +    now = qemu_clock_get_ms(QEMU_CLOCK_HOST);
>> +    if ((ppkt->creation_ms < now) &&
>
> Any case that ppkt->creation_ms >= now?

No, will remove it.

>
>> +        ((now - ppkt->creation_ms) > REGULAR_CHECK_MS)) {
>> + trace_colo_old_packet_check_found(ppkt->creation_ms);
>> +        *found_old = true;
>> +    }
>> +}
>> +
>> +/*
>> + * called from the compare thread on the primary
>> + * for compare connection
>> + */
>> +static void colo_compare_connection(void *opaque, void *user_data)
>> +{
>> +    CompareState *s = user_data;
>> +    Connection *conn = opaque;
>> +    Packet *pkt = NULL;
>> +    GList *result = NULL;
>> +    bool found_old;
>> +    int ret;
>> +
>> +    while (!g_queue_is_empty(&conn->primary_list) &&
>> +           !g_queue_is_empty(&conn->secondary_list)) {
>> +        pkt = g_queue_pop_tail(&conn->primary_list);
>> +        result = g_queue_find_custom(&conn->secondary_list,
>> +                              pkt, 
>> (GCompareFunc)colo_packet_compare_all);
>> +
>> +        if (result) {
>> +            ret = compare_chr_send(s->chr_out, pkt->data, pkt->size);
>> +            if (ret < 0) {
>> +                error_report("colo_send_primary_packet failed");
>> +            }
>> +            trace_colo_compare_main("packet same and release packet");
>> +            g_queue_remove(&conn->secondary_list, result->data);
>> +        } else {
>
> A question I forget the answer, so may ask again. What if secondary 
> packet comes late?

If secondary packet comes late, primary queue has some primary packet.
we use timer to regular call colo_compare_connection(), In here,
we foreach conn->primary_list, if have old primary packet(secondary 
packet comes late),
will call colo_notify_checkpoint() to do a checkpoint,that can make primary
and secondary be same.


>
>> + trace_colo_compare_main("packet different");
>> +            g_queue_push_tail(&conn->primary_list, pkt);
>> +            /* TODO: colo_notify_checkpoint();*/
>> +            break;
>> +        }
>> +    }
>> +
>> +    /*
>> +     * Look for old packets that the secondary hasn't matched,
>> +     * if we have some then we have to checkpoint to wake
>> +     * the secondary up.
>> +     */
>> +    found_old = false;
>> +    g_queue_foreach(&conn->primary_list, colo_old_packet_check, 
>> &found_old);
>> +    if (found_old) {
>> +        /* TODO: colo_notify_checkpoint();*/
>
> Shouldn't we need to remove all "old" packets here?

yes,will add remove func.

>
>> +    }
>> +}
>> +
>>   static int compare_chr_send(CharDriverState *out,
>>                               const uint8_t *buf,
>>                               uint32_t size)
>> @@ -170,6 +278,69 @@ err:
>>       return ret < 0 ? ret : -EIO;
>>   }
>>   +static int compare_chr_can_read(void *opaque)
>> +{
>> +    return COMPARE_READ_LEN_MAX;
>> +}
>> +
>> +/*
>> + * called from the main thread on the primary for packets
>> + * arriving over the socket from the primary.
>> + */
>> +static void compare_pri_chr_in(void *opaque, const uint8_t *buf, int 
>> size)
>> +{
>> +    CompareState *s = COLO_COMPARE(opaque);
>> +    int ret;
>> +
>> +    ret = net_fill_rstate(&s->pri_rs, buf, size);
>> +    if (ret == -1) {
>> +        qemu_chr_add_handlers(s->chr_pri_in, NULL, NULL, NULL, NULL);
>> +        error_report("colo-compare primary_in error");
>> +    }
>> +}
>> +
>> +/*
>> + * called from the main thread on the primary for packets
>> + * arriving over the socket from the secondary.
>> + */
>> +static void compare_sec_chr_in(void *opaque, const uint8_t *buf, int 
>> size)
>> +{
>> +    CompareState *s = COLO_COMPARE(opaque);
>> +    int ret;
>> +
>> +    ret = net_fill_rstate(&s->sec_rs, buf, size);
>> +    if (ret == -1) {
>> +        qemu_chr_add_handlers(s->chr_sec_in, NULL, NULL, NULL, NULL);
>> +        error_report("colo-compare secondary_in error");
>> +    }
>> +}
>> +
>> +static void *colo_compare_thread(void *opaque)
>> +{
>> +    GMainContext *worker_context;
>> +    GMainLoop *compare_loop;
>> +    CompareState *s = opaque;
>> +
>> +    worker_context = g_main_context_new();
>> +    g_assert(g_main_context_get_thread_default() == NULL);
>> +    g_main_context_push_thread_default(worker_context);
>> +    g_assert(g_main_context_get_thread_default() == worker_context);
>> +
>> +    qemu_chr_add_handlers(s->chr_pri_in, compare_chr_can_read,
>> +                          compare_pri_chr_in, NULL, s);
>> +    qemu_chr_add_handlers(s->chr_sec_in, compare_chr_can_read,
>> +                          compare_sec_chr_in, NULL, s);
>> +
>> +    compare_loop = g_main_loop_new(worker_context, FALSE);
>> +
>> +    g_main_loop_run(compare_loop);
>> +
>> +    g_main_loop_unref(compare_loop);
>> +    g_main_context_pop_thread_default(worker_context);
>> +    g_main_context_unref(worker_context);
>> +    return NULL;
>> +}
>> +
>>   static char *compare_get_pri_indev(Object *obj, Error **errp)
>>   {
>>       CompareState *s = COLO_COMPARE(obj);
>> @@ -222,6 +393,9 @@ static void 
>> compare_pri_rs_finalize(SocketReadState *pri_rs)
>>       if (packet_enqueue(s, PRIMARY_IN)) {
>>           trace_colo_compare_main("primary: unsupported packet in");
>>           compare_chr_send(s->chr_out, pri_rs->buf, pri_rs->packet_len);
>> +    } else {
>> +        /* compare connection */
>> +        g_queue_foreach(&s->conn_list, colo_compare_connection, s);
>>       }
>>   }
>>   @@ -231,16 +405,35 @@ static void 
>> compare_sec_rs_finalize(SocketReadState *sec_rs)
>>         if (packet_enqueue(s, SECONDARY_IN)) {
>>           trace_colo_compare_main("secondary: unsupported packet in");
>> +    } else {
>> +        /* compare connection */
>> +        g_queue_foreach(&s->conn_list, colo_compare_connection, s);
>>       }
>>   }
>>     /*
>> + * Prod the compare thread regularly so it can watch for any packets
>> + * that the secondary hasn't produced equivalents of.
>> + */
>> +static void colo_compare_regular(void *opaque)
>> +{
>> +    CompareState *s = opaque;
>> +
>> +    timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
>> +                        REGULAR_CHECK_MS);
>> +    /* compare connection */
>> +    g_queue_foreach(&s->conn_list, colo_compare_connection, s);
>> +}
>
> We need make sure this function was called from colo thread, but it 
> looks not?

Yes, In next version I will make old_packet_check related codes 
independent with
colo_compare_connection().


>
>> +
>> +/*
>>    * called from the main thread on the primary
>>    * to setup colo-compare.
>>    */
>>   static void colo_compare_complete(UserCreatable *uc, Error **errp)
>>   {
>>       CompareState *s = COLO_COMPARE(uc);
>> +    char thread_name[64];
>> +    static int compare_id;
>>         if (!s->pri_indev || !s->sec_indev || !s->outdev) {
>>           error_setg(errp, "colo compare needs 'primary_in' ,"
>> @@ -293,6 +486,19 @@ static void colo_compare_complete(UserCreatable 
>> *uc, Error **errp)
>>                                                         g_free,
>> connection_destroy);
>>   +    s->thread_status = COMPARE_THREAD_RUNNING;
>> +    sprintf(thread_name, "compare %d", compare_id);
>> +    qemu_thread_create(&s->thread, thread_name,
>> +                       colo_compare_thread, s,
>> +                       QEMU_THREAD_JOINABLE);
>> +    compare_id++;
>> +
>> +    /* A regular timer to kick any packets that the secondary 
>> doesn't match */
>> +    s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, /* Only when guest 
>> runs */
>> +                            colo_compare_regular, s);
>> +    timer_mod(s->timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) +
>> +                        REGULAR_CHECK_MS);
>> +
>>       return;
>>   }
>>   @@ -338,6 +544,14 @@ static void colo_compare_finalize(Object *obj)
>>       qemu_mutex_destroy(&s->conn_list_lock);
>>       g_queue_free(&s->conn_list);
>>   +    if (s->thread.thread) {
>> +        s->thread_status = COMPARE_THREAD_EXIT;
>
> Looks like there's not any code that depends on the status, so why 
> need to this>

Currently we needn't this, will move it to "work with colo-frame" 
related patch.

Thanks
Zhang Chen

>
>> +        /* compare connection */
>> +        g_queue_foreach(&s->conn_list, colo_compare_connection, s);
>> +        qemu_thread_join(&s->thread);
>> +    }
>> +    timer_del(s->timer);
>> +
>>       g_free(s->pri_indev);
>>       g_free(s->sec_indev);
>>       g_free(s->outdev);
>> diff --git a/trace-events b/trace-events
>> index 703de1a..1537e91 100644
>> --- a/trace-events
>> +++ b/trace-events
>> @@ -1919,3 +1919,5 @@ aspeed_vic_write(uint64_t offset, unsigned 
>> size, uint32_t data) "To 0x%" PRIx64
>>     # net/colo-compare.c
>>   colo_compare_main(const char *chr) ": %s"
>> +colo_compare_ip_info(int psize, const char *sta, const char *stb, 
>> int ssize, const char *stc, const char *std) "ppkt size = %d, ip_src 
>> = %s, ip_dst = %s, spkt size = %d, ip_src = %s, ip_dst = %s"
>> +colo_old_packet_check_found(int64_t old_time) "%" PRId64
>
>
>
> .
>

-- 
Thanks
zhangchen