* fengzhimin (fengzhim...@huawei.com) wrote: > OK, I will modify it. > > Due to the mach-virt.ram is sent by the multiRDMA channels instead of the > main channel, it don't to register on the main channel.
You might be OK if instead of using the name, you use a size threshold; e.g. you use the multirdma threads for any RAM block larger than say 128MB. > It takes a long time to register the mach-virt.ram for VM with large capacity > memory, so we shall try our best not to register it. I'm curious why, I know it's expensive to register RAM blocks with rdma code; but I thought that would just be the first time; it surprises me that registering it with a 2nd RDMA channel is as expensive. But then that makes me ask a 2nd question; is your performance increase due to multiple threads or is it due to the multiple RDMA channels? COuld you have multiple threads but still a single RDMA channel (and with sufficient locking) still get the performance? Dave > Thanks for your review. > > Zhimin Feng > > -----Original Message----- > From: Dr. David Alan Gilbert [mailto:dgilb...@redhat.com] > Sent: Saturday, January 18, 2020 2:52 AM > To: fengzhimin <fengzhim...@huawei.com> > Cc: quint...@redhat.com; arm...@redhat.com; ebl...@redhat.com; > qemu-devel@nongnu.org; Zhanghailiang <zhang.zhanghaili...@huawei.com>; > jemmy858...@gmail.com > Subject: Re: [PATCH RFC 12/12] migration/rdma: only register the virt-ram > block for MultiRDMA > > * Zhimin Feng (fengzhim...@huawei.com) wrote: > > From: fengzhimin <fengzhim...@huawei.com> > > > > The virt-ram block is sent by MultiRDMA, so we only register it for > > MultiRDMA channels and main channel don't register the virt-ram block. > > > > Signed-off-by: fengzhimin <fengzhim...@huawei.com> > > You can't specialise on the name of the RAMBlock like that. > 'mach-virt.ram' is the name specific to just the main ram on just aarch's > machine type; for example the name on x86 is completely different and if you > use NUMA or hotplug etc it would also be different on aarch. > > Is there a downside to also registering the mach-virt.ram on the main channel? > > Dave > > > --- > > migration/rdma.c | 140 > > +++++++++++++++++++++++++++++++++++++---------- > > 1 file changed, 112 insertions(+), 28 deletions(-) > > > > diff --git a/migration/rdma.c b/migration/rdma.c index > > 0a150099e2..1477fd509b 100644 > > --- a/migration/rdma.c > > +++ b/migration/rdma.c > > @@ -618,7 +618,9 @@ const char *print_wrid(int wrid); static int > > qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head, > > uint8_t *data, RDMAControlHeader *resp, > > int *resp_idx, > > - int (*callback)(RDMAContext *rdma)); > > + int (*callback)(RDMAContext *rdma, > > + uint8_t id), > > + uint8_t id); > > > > static inline uint64_t ram_chunk_index(const uint8_t *start, > > const uint8_t *host) @@ > > -1198,24 +1200,81 @@ static int qemu_rdma_alloc_qp(RDMAContext *rdma) > > return 0; > > } > > > > -static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma) > > +/* > > + * Parameters: > > + * @id == UNUSED_ID : > > + * This means that we register memory for the main RDMA channel, > > + * the main RDMA channel don't register the mach-virt.ram block > > + * when we use multiRDMA method to migrate. > > + * > > + * @id == 0 or id == 1 or ... : > > + * This means that we register memory for the multiRDMA channels, > > + * the multiRDMA channels only register memory for the mach-virt.ram > > + * block when we use multiRDAM method to migrate. > > + */ > > +static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma, uint8_t > > +id) > > { > > int i; > > RDMALocalBlocks *local = &rdma->local_ram_blocks; > > > > - for (i = 0; i < local->nb_blocks; i++) { > > - local->block[i].mr = > > - ibv_reg_mr(rdma->pd, > > - local->block[i].local_host_addr, > > - local->block[i].length, > > - IBV_ACCESS_LOCAL_WRITE | > > - IBV_ACCESS_REMOTE_WRITE > > - ); > > - if (!local->block[i].mr) { > > - perror("Failed to register local dest ram block!\n"); > > - break; > > + if (migrate_use_multiRDMA()) { > > + if (id == UNUSED_ID) { > > + for (i = 0; i < local->nb_blocks; i++) { > > + /* main RDMA channel don't register the mach-virt.ram > > block */ > > + if (strcmp(local->block[i].block_name, "mach-virt.ram") == > > 0) { > > + continue; > > + } > > + > > + local->block[i].mr = > > + ibv_reg_mr(rdma->pd, > > + local->block[i].local_host_addr, > > + local->block[i].length, > > + IBV_ACCESS_LOCAL_WRITE | > > + IBV_ACCESS_REMOTE_WRITE > > + ); > > + if (!local->block[i].mr) { > > + perror("Failed to register local dest ram block!\n"); > > + break; > > + } > > + rdma->total_registrations++; > > + } > > + } else { > > + for (i = 0; i < local->nb_blocks; i++) { > > + /* > > + * The multiRDAM channels only register > > + * the mach-virt.ram block > > + */ > > + if (strcmp(local->block[i].block_name, "mach-virt.ram") == > > 0) { > > + local->block[i].mr = > > + ibv_reg_mr(rdma->pd, > > + local->block[i].local_host_addr, > > + local->block[i].length, > > + IBV_ACCESS_LOCAL_WRITE | > > + IBV_ACCESS_REMOTE_WRITE > > + ); > > + if (!local->block[i].mr) { > > + perror("Failed to register local dest ram > > block!\n"); > > + break; > > + } > > + rdma->total_registrations++; > > + } > > + } > > + } > > + } else { > > + for (i = 0; i < local->nb_blocks; i++) { > > + local->block[i].mr = > > + ibv_reg_mr(rdma->pd, > > + local->block[i].local_host_addr, > > + local->block[i].length, > > + IBV_ACCESS_LOCAL_WRITE | > > + IBV_ACCESS_REMOTE_WRITE > > + ); > > + if (!local->block[i].mr) { > > + perror("Failed to register local dest ram block!\n"); > > + break; > > + } > > + rdma->total_registrations++; > > } > > - rdma->total_registrations++; > > } > > > > if (i >= local->nb_blocks) { > > @@ -1223,8 +1282,10 @@ static int > > qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma) > > } > > > > for (i--; i >= 0; i--) { > > - ibv_dereg_mr(local->block[i].mr); > > - rdma->total_registrations--; > > + if (local->block[i].mr) { > > + ibv_dereg_mr(local->block[i].mr); > > + rdma->total_registrations--; > > + } > > } > > > > return -1; > > @@ -1446,7 +1507,7 @@ static int qemu_rdma_unregister_waiting(RDMAContext > > *rdma) > > reg.key.chunk = chunk; > > register_to_network(rdma, ®); > > ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®, > > - &resp, NULL, NULL); > > + &resp, NULL, NULL, UNUSED_ID); > > if (ret < 0) { > > return ret; > > } > > @@ -1915,11 +1976,17 @@ static void qemu_rdma_move_header(RDMAContext > > *rdma, int idx, > > * The extra (optional) response is used during registration to us from > > having > > * to perform an *additional* exchange of message just to provide a > > response by > > * instead piggy-backing on the acknowledgement. > > + * > > + * Parameters: > > + * @id : callback function need two parameters, id is the second > > parameter. > > + * > > */ > > static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader > > *head, > > uint8_t *data, RDMAControlHeader *resp, > > int *resp_idx, > > - int (*callback)(RDMAContext *rdma)) > > + int (*callback)(RDMAContext *rdma, > > + uint8_t id), > > + uint8_t id) > > { > > int ret = 0; > > > > @@ -1973,7 +2040,7 @@ static int qemu_rdma_exchange_send(RDMAContext *rdma, > > RDMAControlHeader *head, > > if (resp) { > > if (callback) { > > trace_qemu_rdma_exchange_send_issue_callback(); > > - ret = callback(rdma); > > + ret = callback(rdma, id); > > if (ret < 0) { > > return ret; > > } > > @@ -2168,7 +2235,7 @@ retry: > > > > compress_to_network(rdma, &comp); > > ret = qemu_rdma_exchange_send(rdma, &head, > > - (uint8_t *) &comp, NULL, NULL, NULL); > > + (uint8_t *) &comp, NULL, NULL, NULL, > > + UNUSED_ID); > > > > if (ret < 0) { > > return -EIO; > > @@ -2195,7 +2262,7 @@ retry: > > > > register_to_network(rdma, ®); > > ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®, > > - &resp, ®_result_idx, NULL); > > + &resp, ®_result_idx, NULL, > > + UNUSED_ID); > > if (ret < 0) { > > return ret; > > } > > @@ -2828,7 +2895,8 @@ static ssize_t qio_channel_rdma_writev(QIOChannel > > *ioc, > > head.len = len; > > head.type = RDMA_CONTROL_QEMU_FILE; > > > > - ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL, > > NULL); > > + ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, > > + NULL, NULL, UNUSED_ID); > > > > if (ret < 0) { > > rdma->error_state = ret; @@ -3660,7 +3728,7 @@ static > > int qemu_rdma_registration_handle(QEMUFile *f, void *opaque) > > } > > > > if (rdma->pin_all) { > > - ret = qemu_rdma_reg_whole_ram_blocks(rdma); > > + ret = qemu_rdma_reg_whole_ram_blocks(rdma, > > + UNUSED_ID); > > if (ret) { > > error_report("rdma migration: error dest " > > "registering ram blocks"); @@ > > -3675,6 +3743,15 @@ static int qemu_rdma_registration_handle(QEMUFile *f, > > void *opaque) > > * their "local" descriptions with what was sent. > > */ > > for (i = 0; i < local->nb_blocks; i++) { > > + /* > > + * use the main RDMA channel to deliver the block of device > > + * use the multiRDMA channels to deliver the RAMBlock > > + */ > > + if (migrate_use_multiRDMA() && > > + strcmp(local->block[i].block_name, "mach-virt.ram") == > > 0) { > > + continue; > > + } > > + > > rdma->dest_blocks[i].remote_host_addr = > > (uintptr_t)(local->block[i].local_host_addr); > > > > @@ -3992,7 +4069,7 @@ static int qemu_rdma_registration_stop(QEMUFile *f, > > void *opaque, > > */ > > ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp, > > ®_result_idx, rdma->pin_all ? > > - qemu_rdma_reg_whole_ram_blocks : NULL); > > + qemu_rdma_reg_whole_ram_blocks : NULL, > > + UNUSED_ID); > > if (ret < 0) { > > ERROR(errp, "receiving remote info!"); > > return ret; > > @@ -4025,6 +4102,11 @@ static int qemu_rdma_registration_stop(QEMUFile *f, > > void *opaque, > > memcpy(rdma->dest_blocks, > > rdma->wr_data[reg_result_idx].control_curr, resp.len); > > for (i = 0; i < nb_dest_blocks; i++) { > > + if (migrate_use_multiRDMA() && > > + strcmp(local->block[i].block_name, "mach-virt.ram") == 0) { > > + continue; > > + } > > + > > network_to_dest_block(&rdma->dest_blocks[i]); > > > > /* We require that the blocks are in the same order */ @@ > > -4050,7 +4132,8 @@ static int qemu_rdma_registration_stop(QEMUFile *f, void > > *opaque, > > trace_qemu_rdma_registration_stop(flags); > > > > head.type = RDMA_CONTROL_REGISTER_FINISHED; > > - ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL); > > + ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, > > + NULL, NULL, UNUSED_ID); > > > > if (migrate_use_multiRDMA()) { > > /* > > @@ -4298,7 +4381,7 @@ static int qemu_multiRDMA_registration_handle(void > > *opaque) > > sizeof(RDMALocalBlock), dest_ram_sort_func); > > > > if (rdma->pin_all) { > > - ret = qemu_rdma_reg_whole_ram_blocks(rdma); > > + ret = qemu_rdma_reg_whole_ram_blocks(rdma, p->id); > > if (ret) { > > error_report("rdma migration: error dest " > > "registering ram blocks"); @@ > > -4680,7 +4763,7 @@ static void *multiRDMA_send_thread(void *opaque) > > > > ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp, > > ®_result_idx, rdma->pin_all ? > > - qemu_rdma_reg_whole_ram_blocks : NULL); > > + qemu_rdma_reg_whole_ram_blocks : NULL, p->id); > > if (ret < 0) { > > return NULL; > > } > > @@ -4749,7 +4832,8 @@ static void *multiRDMA_send_thread(void *opaque) > > > > /* Send FINISHED to the destination */ > > head.type = RDMA_CONTROL_REGISTER_FINISHED; > > - ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL); > > + ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, > > + NULL, NULL, p->id); > > if (ret < 0) { > > return NULL; > > } > > -- > > 2.19.1 > > > > > -- > Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
