On Tue, Nov 28, 2017 at 8:04 PM, Mao Zhongyi <maozy.f...@cn.fujitsu.com> wrote:
> The primary and secondary guest has the same TCP stream, but the > the packet sizes are different due to the different fragmentation. > > In the current impletation, compare the packet with the size of > payload, but packets of the same size and payload are very few, > so it triggers checkopint frequently, which leads to a very low > performance of the tcp packet comparison. In addtion, the method > of comparing the size of packet is not correct in itself. > > like that: > We send this payload: > ------------------------------ > | header |1|2|3|4|5|6|7|8|9|0| > ------------------------------ > > primary: > ppkt1: > ---------------- > | header |1|2|3| > ---------------- > ppkt2: > ------------------------ > | header |4|5|6|7|8|9|0| > ------------------------ > > secondary: > spkt1: > ------------------------------ > | header |1|2|3|4|5|6|7|8|9|0| > ------------------------------ > > In the original method, ppkt1 and ppkt2 are diffrent in size and > spkt1, so they can't compare and trigger the checkpoint. > > I have tested FTP get 200M and 1G file many times, I found that > the performance was less than 1% of the native. > > Now I reconstructed the comparison of TCP packets based on the > TCP sequence number. first of all, ppkt1 and spkt1 have the same > starting sequence number, so they can compare, even though their > length is different. And then ppkt1 with a smaller payload length > is used as the comparison length, if the payload is same, send > out the ppkt1 and record the offset(the length of ppkt1 payload) > in spkt1. The next comparison, ppkt2 and spkt1 can be compared > from the recorded position of spkt1. > > like that: > ---------------- > | header |1|2|3| ppkt1 > ---------|-----| > | | > ---------v-----v-------------- > | header |1|2|3|4|5|6|7|8|9|0| spkt1 > ---------------|\------------| > | \offset | > ---------v-------------v > | header |4|5|6|7|8|9|0| ppkt2 > ------------------------ > > In this way, the performance can reach native 20% in my multiple > tests. > > Cc: Zhang Chen <zhangc...@gmail.com> > Cc: Li Zhijian <lizhij...@cn.fujitsu.com> > Cc: Jason Wang <jasow...@redhat.com> > > Reported-by: Zhang Chen <zhangc...@gmail.com> > Signed-off-by: Mao Zhongyi <maozy.f...@cn.fujitsu.com> > Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com> > --- > net/colo-compare.c | 300 ++++++++++++++++++++++++++++++ > +++-------------------- > net/colo.c | 8 ++ > net/colo.h | 14 +++ > 3 files changed, 211 insertions(+), 111 deletions(-) > > diff --git a/net/colo-compare.c b/net/colo-compare.c > index 1ce195f..0752e9f 100644 > --- a/net/colo-compare.c > +++ b/net/colo-compare.c > @@ -38,6 +38,9 @@ > #define COMPARE_READ_LEN_MAX NET_BUFSIZE > #define MAX_QUEUE_SIZE 1024 > > +#define COLO_COMPARE_FREE_PRIMARY 0x01 > +#define COLO_COMPARE_FREE_SECONDARY 0x02 > + > /* TODO: Should be configurable */ > #define REGULAR_PACKET_CHECK_MS 3000 > > @@ -112,14 +115,31 @@ static gint seq_sorter(Packet *a, Packet *b, > gpointer data) > return ntohl(atcp->th_seq) - ntohl(btcp->th_seq); > } > > +static void fill_pkt_seq(void *data, uint32_t *max_ack) > +{ > + Packet *pkt = data; > + struct tcphdr *tcphd; > + > + tcphd = (struct tcphdr *)pkt->transport_header; > + > + pkt->tcp_seq = ntohl(tcphd->th_seq); > + pkt->tcp_ack = ntohl(tcphd->th_ack); > + *max_ack = *max_ack > pkt->tcp_ack ? *max_ack : pkt->tcp_ack; > + pkt->hdsize = pkt->transport_header - (uint8_t *)pkt->data > + + (tcphd->th_off << 2) - pkt->vnet_hdr_len; > + pkt->pdsize = pkt->size - pkt->hdsize; > In this function you are not just "fill_pkt_seq", use "fill_pkt_tcp_info" is more suitable. And use "header_size" and "payload_size" instead of "hdsize" and "pdsize" maybe better to read. > + pkt->seq_end = pkt->tcp_seq + pkt->pdsize; > +} > + > /* > * Return 1 on success, if return 0 means the > * packet will be dropped > */ > -static int colo_insert_packet(GQueue *queue, Packet *pkt) > +static int colo_insert_packet(GQueue *queue, Packet *pkt, uint32_t > *max_ack) > { > if (g_queue_get_length(queue) <= MAX_QUEUE_SIZE) { > if (pkt->ip->ip_p == IPPROTO_TCP) { > + fill_pkt_seq(pkt, max_ack); > g_queue_insert_sorted(queue, > pkt, > (GCompareDataFunc)seq_sorter, > @@ -169,12 +189,12 @@ static int packet_enqueue(CompareState *s, int mode, > Connection **con) > } > > if (mode == PRIMARY_IN) { > - if (!colo_insert_packet(&conn->primary_list, pkt)) { > + if (!colo_insert_packet(&conn->primary_list, pkt, &conn->pack)) { > error_report("colo compare primary queue size too big," > "drop packet"); > } > } else { > - if (!colo_insert_packet(&conn->secondary_list, pkt)) { > + if (!colo_insert_packet(&conn->secondary_list, pkt, > &conn->sack)) { > error_report("colo compare secondary queue size too big," > "drop packet"); > } > @@ -184,6 +204,167 @@ static int packet_enqueue(CompareState *s, int mode, > Connection **con) > return 0; > } > > +static inline bool after(uint32_t seq1, uint32_t seq2) > +{ > + return (int32_t)(seq1 - seq2) > 0; > +} > + > +static void colo_release_primary_pkt(CompareState *s, Packet *pkt) > +{ > + int ret; > + ret = compare_chr_send(s, > + pkt->data, > + pkt->size, > + pkt->vnet_hdr_len); > + if (ret < 0) { > + error_report("colo send primary packet failed"); > + } > + trace_colo_compare_main("packet same and release packet"); > + packet_destroy(pkt, NULL); > +} > This function codes duplicate with that in colo_compare_connection(), We'd better reuse it. > + > +static bool colo_compare_payload(Packet *ppkt, Packet *spkt, > + uint16_t poff, uint16_t soff, > + uint16_t len) > +{ > + if (memcmp(ppkt->data + poff, spkt->data + soff, len)) { > + trace_colo_compare_main("the payload is not same"); > + return false; > + } > + return true; > +} > This function looks like colo_packet_compare_common(), Why we need add a new one? > + > +/* > + * return true means that the payload is consist and > + * need to make the next comparison, false means do > + * the checkpoint > + */ > +static bool colo_mark_tcp_pkt(Packet *ppkt, Packet *spkt, > + int8_t *mark, uint32_t max_ack) > +{ > + *mark = 0; > + > + if (ppkt->tcp_seq == spkt->tcp_seq && ppkt->seq_end == spkt->seq_end) > { > + if (colo_compare_payload(ppkt, spkt, ppkt->hdsize, spkt->hdsize, > + ppkt->hdsize)) { > + *mark = COLO_COMPARE_FREE_SECONDARY | > COLO_COMPARE_FREE_PRIMARY; > + return true; > + } > + } > + > + /* one part of secondary packet payload still need to be compared */ > + if (!after(ppkt->seq_end, spkt->seq_end)) { > + if (colo_compare_payload(ppkt, spkt, ppkt->hdsize + ppkt->offset, > + spkt->hdsize + spkt->offset, > + ppkt->pdsize - ppkt->offset)) { > + if (!after(ppkt->tcp_ack, max_ack)) { > + *mark = COLO_COMPARE_FREE_PRIMARY; > + spkt->offset += ppkt->pdsize - ppkt->offset; > + return true; > + } else { > + /* secondary guest hasn't ack the data, don't send > + * out this packet > + */ > + return false; > + } > + } > + } else { > + /* primary packet is longer than secondary packet, compare > + * the same part and mark the primary packet offset > + */ > + if (colo_compare_payload(ppkt, spkt, ppkt->hdsize + ppkt->offset, > + spkt->hdsize + spkt->offset, > + spkt->pdsize - spkt->offset)) { > + *mark = COLO_COMPARE_FREE_SECONDARY; > + ppkt->offset += spkt->pdsize - spkt->offset; > + return true; > + } > + } > + > + return false; > +} > + > +static void colo_compare_tcp(CompareState *s, Connection *conn) > +{ > + Packet *ppkt = NULL, *spkt = NULL; > + int8_t mark; > You should add more comments about the "max_ack". > + uint32_t max_ack = conn->pack > conn->sack ? conn->sack : conn->pack; > + > +pri: > + if (g_queue_is_empty(&conn->primary_list)) { > + return; > + } > + ppkt = g_queue_pop_head(&conn->primary_list); > +sec: > + if (g_queue_is_empty(&conn->secondary_list)) { > + g_queue_push_head(&conn->primary_list, ppkt); > + return; > + } > + spkt = g_queue_pop_head(&conn->secondary_list); > + > + if (ppkt->tcp_seq == ppkt->seq_end) { > + colo_release_primary_pkt(s, ppkt); > + ppkt = NULL; > + } > + > + if (ppkt && conn->compare_seq && !after(ppkt->seq_end, > conn->compare_seq)) { > + trace_colo_compare_main("pri: pkt has compared & posted, > destroy"); > + packet_destroy(ppkt, NULL); > + ppkt = NULL; > + } > + > + if (spkt->tcp_seq == spkt->seq_end) { > + packet_destroy(spkt, NULL); > + if (!ppkt) { > + goto pri; > + } else { > + goto sec; > + } > + } else { > + if (conn->compare_seq && !after(spkt->seq_end, > conn->compare_seq)) { > + trace_colo_compare_main("sec: pkt has compared & posted, > destroy"); > + packet_destroy(spkt, NULL); > + if (!ppkt) { > + goto pri; > + } else { > + goto sec; > + } > + } > + if (!ppkt) { > + g_queue_push_head(&conn->secondary_list, spkt); > + goto pri; > + } > + } > + > + if (colo_mark_tcp_pkt(ppkt, spkt, &mark, max_ack)) { > + if (mark == COLO_COMPARE_FREE_PRIMARY) { > + conn->compare_seq = ppkt->seq_end; > + colo_release_primary_pkt(s, ppkt); > + g_queue_push_head(&conn->secondary_list, spkt); > + goto pri; > + } > + if (mark == COLO_COMPARE_FREE_SECONDARY) { > + conn->compare_seq = spkt->seq_end; > + packet_destroy(spkt, NULL); > + goto sec; > + } > + if (mark == (COLO_COMPARE_FREE_PRIMARY | > COLO_COMPARE_FREE_SECONDARY)) { > + conn->compare_seq = ppkt->seq_end; > + colo_release_primary_pkt(s, ppkt); > + packet_destroy(spkt, NULL); > + goto pri; > + } > + } else { > + g_queue_push_head(&conn->primary_list, ppkt); > + g_queue_push_head(&conn->secondary_list, spkt); > + > + /* > + * colo_compare_inconsistent_notify(); > + * TODO: notice to checkpoint(); > + */ > + } > +} > + > /* > * The IP packets sent by primary and secondary > * will be compared in here > @@ -224,110 +405,6 @@ static int colo_packet_compare_common(Packet *ppkt, > > /* > * Called from the compare thread on the primary > - * for compare tcp packet > - * compare_tcp copied from Dr. David Alan Gilbert's branch > - */ > -static int colo_packet_compare_tcp(Packet *spkt, Packet *ppkt) > -{ > - struct tcphdr *ptcp, *stcp; > - int res; > - > - trace_colo_compare_main("compare tcp"); > - > - ptcp = (struct tcphdr *)ppkt->transport_header; > - stcp = (struct tcphdr *)spkt->transport_header; > - > - /* > - * The 'identification' field in the IP header is *very* random > - * it almost never matches. Fudge this by ignoring differences in > - * unfragmented packets; they'll normally sort themselves out if > different > - * anyway, and it should recover at the TCP level. > - * An alternative would be to get both the primary and secondary to > rewrite > - * somehow; but that would need some sync traffic to sync the state > - */ > - if (ntohs(ppkt->ip->ip_off) & IP_DF) { > - spkt->ip->ip_id = ppkt->ip->ip_id; > - /* and the sum will be different if the IDs were different */ > - spkt->ip->ip_sum = ppkt->ip->ip_sum; > - } > - > - /* > - * Check tcp header length for tcp option field. > - * th_off > 5 means this tcp packet have options field. > - * The tcp options maybe always different. > - * for example: > - * From RFC 7323. > - * TCP Timestamps option (TSopt): > - * Kind: 8 > - * > - * Length: 10 bytes > - * > - * +-------+-------+---------------------+---------------------+ > - * |Kind=8 | 10 | TS Value (TSval) |TS Echo Reply (TSecr)| > - * +-------+-------+---------------------+---------------------+ > - * 1 1 4 4 > - * > - * In this case the primary guest's timestamp always different with > - * the secondary guest's timestamp. COLO just focus on payload, > - * so we just need skip this field. > - */ > - if (ptcp->th_off > 5) { > - ptrdiff_t ptcp_offset, stcp_offset; > - > - ptcp_offset = ppkt->transport_header - (uint8_t *)ppkt->data > - + (ptcp->th_off * 4) - ppkt->vnet_hdr_len; > - stcp_offset = spkt->transport_header - (uint8_t *)spkt->data > - + (stcp->th_off * 4) - spkt->vnet_hdr_len; > - > - /* > - * When network is busy, some tcp options(like sack) will > unpredictable > - * occur in primary side or secondary side. it will make packet > size > - * not same, but the two packet's payload is identical. colo just > - * care about packet payload, so we skip the option field. > - */ > - res = colo_packet_compare_common(ppkt, spkt, ptcp_offset, > stcp_offset); > - } else if (ptcp->th_sum == stcp->th_sum) { > - res = colo_packet_compare_common(ppkt, spkt, ETH_HLEN, ETH_HLEN); > - } else { > - res = -1; > - } > - > - if (res != 0 && > - trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) { > - char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], > sec_ip_dst[20]; > - > - strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src)); > - strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst)); > - strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src)); > - strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst)); > - > - trace_colo_compare_ip_info(ppkt->size, pri_ip_src, > - pri_ip_dst, spkt->size, > - sec_ip_src, sec_ip_dst); > - > - trace_colo_compare_tcp_info("pri tcp packet", > - ntohl(ptcp->th_seq), > - ntohl(ptcp->th_ack), > - res, ptcp->th_flags, > - ppkt->size); > - > - trace_colo_compare_tcp_info("sec tcp packet", > - ntohl(stcp->th_seq), > - ntohl(stcp->th_ack), > - res, stcp->th_flags, > - spkt->size); > - > - qemu_hexdump((char *)ppkt->data, stderr, > - "colo-compare ppkt", ppkt->size); > - qemu_hexdump((char *)spkt->data, stderr, > - "colo-compare spkt", spkt->size); > - } > - > - return res; > -} > - > -/* > - * Called from the compare thread on the primary > * for compare udp packet > */ > static int colo_packet_compare_udp(Packet *spkt, Packet *ppkt) > @@ -492,14 +569,15 @@ static void colo_compare_connection(void *opaque, > void *user_data) > GList *result = NULL; > int ret; > > + if (conn->ip_proto == IPPROTO_TCP) { > + colo_compare_tcp(s, conn); > + return; > + } > + > while (!g_queue_is_empty(&conn->primary_list) && > !g_queue_is_empty(&conn->secondary_list)) { > pkt = g_queue_pop_head(&conn->primary_list); > switch (conn->ip_proto) { > - case IPPROTO_TCP: > - result = g_queue_find_custom(&conn->secondary_list, > - pkt, (GCompareFunc)colo_packet_compare_tcp); > - break; > I think we should put colo_compare_tcp in here, like other protocol. If this compare loop can't satisfy your needs(like goto pri/sec), you can fix this loop that make it more general, rather than give TCP a privilege between other protocol(like compare firstly). Thanks Zhang Chen > case IPPROTO_UDP: > result = g_queue_find_custom(&conn->secondary_list, > pkt, (GCompareFunc)colo_packet_compare_udp); > diff --git a/net/colo.c b/net/colo.c > index a39d600..1743522 100644 > --- a/net/colo.c > +++ b/net/colo.c > @@ -138,6 +138,8 @@ Connection *connection_new(ConnectionKey *key) > conn->processing = false; > conn->offset = 0; > conn->syn_flag = 0; > + conn->pack = 0; > + conn->sack = 0; > g_queue_init(&conn->primary_list); > g_queue_init(&conn->secondary_list); > > @@ -163,6 +165,12 @@ Packet *packet_new(const void *data, int size, int > vnet_hdr_len) > pkt->size = size; > pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_HOST); > pkt->vnet_hdr_len = vnet_hdr_len; > + pkt->tcp_seq = 0; > + pkt->tcp_ack = 0; > + pkt->seq_end = 0; > + pkt->hdsize = 0; > + pkt->pdsize = 0; > + pkt->offset = 0; > > return pkt; > } > diff --git a/net/colo.h b/net/colo.h > index 0658e86..97bc41e 100644 > --- a/net/colo.h > +++ b/net/colo.h > @@ -45,6 +45,14 @@ typedef struct Packet { > int64_t creation_ms; > /* Get vnet_hdr_len from filter */ > uint32_t vnet_hdr_len; > + uint32_t tcp_seq; /* sequence number */ > + uint32_t tcp_ack; /* acknowledgement number */ > + /* the sequence number of the last byte of the packet */ > + uint32_t seq_end; > + uint8_t hdsize; /* the header length */ > + uint16_t pdsize; /* the payload length */ > + /* record the payload offset(the length that has been compared) */ > + uint16_t offset; > } Packet; > > typedef struct ConnectionKey { > @@ -64,6 +72,12 @@ typedef struct Connection { > /* flag to enqueue unprocessed_connections */ > bool processing; > uint8_t ip_proto; > + /* record the sequence number that has been compared */ > + uint32_t compare_seq; > + /* the maximum of acknowledgement number in primary_list queue */ > + uint32_t pack; > + /* the maximum of acknowledgement number in secondary_list queue */ > + uint32_t sack; > /* offset = secondary_seq - primary_seq */ > tcp_seq offset; > /* > -- > 2.9.4 > > > >