The current bandwidth calculation aggregates all the targets. This simple method does not take into account where multiple targets sharing under a switch where the aggregated bandwidth can be less or greater than the upstream link of the switch. To accurately account for the shared upstream uplink cases, a new update function is introduced by walking from the leaves to the root of the hierachy and adjust the bandwidth in the process. This process is done when all the targets for a region is present but before the final values are send to the HMAT handling code cached access_coordinate targets. The original perf calculation path was kept to calculate the configurations without switches and also keep the latency data as that does not require special calculation. The shared upstream link calculation is done as a second pass when all the endpoints have arrived. Suggested-by: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx> Link: https://lore.kernel.org/linux-cxl/20240501152503.00002e60@xxxxxxxxxx/ Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx> --- v3: - Redo calculation based on Jonathan's suggestion. (Jonathan) --- drivers/cxl/core/cdat.c | 380 ++++++++++++++++++++++++++++++++++++-- drivers/cxl/core/core.h | 4 +- drivers/cxl/core/pci.c | 21 +++ drivers/cxl/core/port.c | 26 +++ drivers/cxl/core/region.c | 4 + drivers/cxl/cxl.h | 1 + 6 files changed, 418 insertions(+), 18 deletions(-) diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c index fea214340d4b..e77b416b0fe0 100644 --- a/drivers/cxl/core/cdat.c +++ b/drivers/cxl/core/cdat.c @@ -548,32 +548,378 @@ void cxl_coordinates_combine(struct access_coordinate *out, MODULE_IMPORT_NS(CXL); -void cxl_region_perf_data_calculate(struct cxl_region *cxlr, - struct cxl_endpoint_decoder *cxled) +static void cxl_bandwidth_add(struct access_coordinate *coord, + struct access_coordinate *c1, + struct access_coordinate *c2) { - struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); - struct cxl_dev_state *cxlds = cxlmd->cxlds; - struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds); - struct range dpa = { - .start = cxled->dpa_res->start, - .end = cxled->dpa_res->end, - }; - struct cxl_dpa_perf *perf; + for (int i = 0; i < ACCESS_COORDINATE_MAX; i++) { + coord[i].read_bandwidth = c1[i].read_bandwidth + + c2[i].read_bandwidth; + coord[i].write_bandwidth = c1[i].write_bandwidth + + c2[i].write_bandwidth; + } +} - switch (cxlr->mode) { +struct cxl_perf_ctx { + struct access_coordinate coord[ACCESS_COORDINATE_MAX]; + struct cxl_port *port; +}; + +static struct cxl_dpa_perf *cxl_memdev_get_dpa_perf(struct cxl_memdev_state *mds, + enum cxl_decoder_mode mode) +{ + switch (mode) { case CXL_DECODER_RAM: - perf = &mds->ram_perf; - break; + return &mds->ram_perf; case CXL_DECODER_PMEM: - perf = &mds->pmem_perf; - break; + return &mds->pmem_perf; default: - return; + break; } - lockdep_assert_held(&cxl_dpa_rwsem); + return ERR_PTR(-EINVAL); +} + +static bool dpa_perf_contains(struct cxl_dpa_perf *perf, + struct resource *dpa_res) +{ + struct range dpa = { + .start = dpa_res->start, + .end = dpa_res->end, + }; if (!range_contains(&perf->dpa_range, &dpa)) + return false; + + return true; +} + +static int cxl_endpoint_gather_coordinates(struct cxl_region *cxlr, + struct cxl_endpoint_decoder *cxled, + struct xarray *usp_xa) +{ + struct cxl_port *endpoint = to_cxl_port(cxled->cxld.dev.parent); + struct access_coordinate pci_coord[ACCESS_COORDINATE_MAX]; + struct access_coordinate sw_coord[ACCESS_COORDINATE_MAX]; + struct access_coordinate ep_coord[ACCESS_COORDINATE_MAX]; + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); + struct cxl_dev_state *cxlds = cxlmd->cxlds; + struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds); + struct pci_dev *pdev = to_pci_dev(cxlds->dev); + struct cxl_perf_ctx *c __free(kfree) = NULL; + struct cxl_perf_ctx *perf_ctx; + struct cxl_port *parent_port; + struct cxl_dpa_perf *perf; + unsigned long index; + void *ptr; + int rc; + + if (cxlds->rcd) + return -ENODEV; + + parent_port = to_cxl_port(endpoint->dev.parent); + /* No CXL switch upstream then skip out. */ + if (is_cxl_root(parent_port)) + return -ENODEV; + + perf = cxl_memdev_get_dpa_perf(mds, cxlr->mode); + if (IS_ERR(perf)) + return PTR_ERR(perf); + + if (!dpa_perf_contains(perf, cxled->dpa_res)) + return -EINVAL; + + /* + * The index for the xarray is the upstream port device of the upstream + * CXL switch. + */ + index = (unsigned long)(unsigned long *)parent_port->uport_dev; + perf_ctx = xa_load(usp_xa, index); + if (!perf_ctx) { + c = kzalloc(sizeof(*perf_ctx), GFP_KERNEL); + if (!c) + return -ENOMEM; + ptr = xa_store(usp_xa, index, c, GFP_KERNEL); + if (xa_is_err(ptr)) + return xa_err(ptr); + perf_ctx = no_free_ptr(c); + } + + /* Upstream link bandwidth */ + rc = cxl_pci_get_bandwidth(pdev, pci_coord); + if (rc < 0) + return rc; + + /* Min of upstream link bandwidth and Endpoint CDAT bandwidth from DSLBIS */ + cxl_coordinates_combine(ep_coord, pci_coord, perf->cdat_coord); + + /* + * Retrieve the switch SSLBIS for switch downstream port associated with + * the endpoint bandwidth. + */ + rc = cxl_port_get_switch_dport_bandwidth(endpoint, sw_coord); + if (rc) + return rc; + + /* Min of the earlier coordinates with the switch SSLBIS bandwidth */ + cxl_coordinates_combine(ep_coord, ep_coord, sw_coord); + + /* + * Aggregate the computed bandwidth with the current aggregated bandwidth + * of the endpoints with the same upstream switch port. + */ + cxl_bandwidth_add(perf_ctx->coord, perf_ctx->coord, ep_coord); + perf_ctx->port = parent_port; + + return 0; +} + +static struct xarray *cxl_switch_iterate_coordinates(struct xarray *input_xa) +{ + struct xarray *res_xa __free(kfree) = kzalloc(sizeof(*res_xa), GFP_KERNEL); + struct access_coordinate coords[ACCESS_COORDINATE_MAX]; + struct cxl_perf_ctx *n __free(kfree) = NULL; + struct cxl_perf_ctx *ctx, *us_ctx; + unsigned long index, key; + bool is_root = false; + void *ptr; + int rc; + + if (!res_xa) + return ERR_PTR(-ENOMEM); + xa_init(res_xa); + + xa_for_each(input_xa, index, ctx) { + struct device *dev = (struct device *)(unsigned long *)index; + struct cxl_port *parent_port, *port; + struct cxl_dport *dport; + struct pci_dev *pdev; + + port = ctx->port; + parent_port = to_cxl_port(port->dev.parent); + dport = port->parent_dport; + /* + * If parent port is CXL root port, then take the min of the parent + * dport bandwidth, which comes from the generic target via ACPI + * tables (SRAT & HMAT), and the bandwidth in the xarray. Then + * update the bandwidth in the xarray. + */ + if (is_cxl_root(parent_port)) { + ctx->port = parent_port; + cxl_coordinates_combine(ctx->coord, ctx->coord, + dport->coord); + is_root = true; + continue; + } + + /* Below is the calculation for another switch upstream */ + + /* + * If the device isn't an upstream PCIe port, there's something + * wrong with the topology. + */ + if (!dev_is_pci(dev)) + return ERR_PTR(-EINVAL); + + /* Retrieve the upstream link bandwidth */ + pdev = to_pci_dev(dev); + rc = cxl_pci_get_bandwidth(pdev, coords); + if (rc) + return ERR_PTR(-ENXIO); + + /* + * Take the min of downstream bandwidth and the upstream link + * bandwidth. + */ + cxl_coordinates_combine(coords, coords, ctx->coord); + /* + * Take the min of the calculated bandwdith and the upstream + * switch SSLBIS bandwidth. + */ + cxl_coordinates_combine(coords, coords, dport->coord); + + /* + * Create an xarray entry with the key of the upstream + * port of the upstream switch. + */ + key = (unsigned long)(unsigned long *)parent_port->uport_dev; + us_ctx = xa_load(res_xa, key); + if (!us_ctx) { + n = kzalloc(sizeof(*n), GFP_KERNEL); + if (!n) + return ERR_PTR(-ENOMEM); + ptr = xa_store(res_xa, key, n, GFP_KERNEL); + if (xa_is_err(ptr)) + return ERR_PTR(xa_err(ptr)); + us_ctx = no_free_ptr(n); + } + + /* + * Aggregate the bandwidth based on the upstream switch. + */ + cxl_bandwidth_add(us_ctx->coord, us_ctx->coord, coords); + us_ctx->port = parent_port; + } + + if (is_root) + return NULL; + + return_ptr(res_xa); +} + +static void cxl_region_update_access_coordinate(struct cxl_region *cxlr, + struct xarray *input_xa) +{ + struct access_coordinate coord[ACCESS_COORDINATE_MAX]; + struct cxl_perf_ctx *ctx; + unsigned long index; + + memset(coord, 0, sizeof(coord)); + xa_for_each(input_xa, index, ctx) + cxl_bandwidth_add(coord, coord, ctx->coord); + + for (int i = 0; i < ACCESS_COORDINATE_MAX; i++) { + cxlr->coord[i].read_bandwidth = coord[i].read_bandwidth; + cxlr->coord[i].write_bandwidth = coord[i].write_bandwidth; + } +} + +static void free_perf_xa(struct xarray *xa) +{ + struct cxl_perf_ctx *ctx; + unsigned long index; + + if (!xa) + return; + + xa_for_each(xa, index, ctx) + kfree(ctx); + xa_destroy(xa); + kfree(xa); +} + +/* + * cxl_region_shared_upstream_perf_update - Recalculate the access coordinates + * @cxl_region: the cxl region to recalculate + * + * For certain region construction with endpoints behind CXL switches, + * there is the possibility of the total bandwdith for all the endpoints + * behind a switch between less or more than the switch upstream link. The + * algorithm assumes the configuration is a symmetric topology that puts + * max performance into consideration. For a region topology without switch + * involvement, the code exits without doing computation. + * + * An example hierachy: + * + * CFMWS 0 + * | + * _________|_________ + * | | + * GP0/HB0/ACPI0017-0 GP1/HB1/ACPI0017-1 + * | | | | + * RP0 RP1 RP2 RP3 + * | | | | + * SW 0 SW 1 SW 2 SW 3 + * | | | | | | | | + * EP0 EP1 EP2 EP3 EP4 EP5 EP6 EP7 + * + * Computation for the example hierachy: + * + * Min (GP0 to CPU BW, + * Min(SW 0 Upstream Link to RP0 BW, + * Min(SW0SSLBIS for SW0DSP0 (EP0), EP0 DSLBIS, EP0 Upstream Link) + + * Min(SW0SSLBIS for SW0DSP1 (EP1), EP1 DSLBIS, EP1 Upstream link)) + + * Min(SW 1 Upstream Link to RP1 BW, + * Min(SW1SSLBIS for SW1DSP0 (EP2), EP2 DSLBIS, EP2 Upstream Link) + + * Min(SW1SSLBIS for SW1DSP1 (EP3), EP3 DSLBIS, EP3 Upstream link))) + + * Min (GP1 to CPU BW, + * Min(SW 2 Upstream Link to RP2 BW, + * Min(SW2SSLBIS for SW2DSP0 (EP4), EP4 DSLBIS, EP4 Upstream Link) + + * Min(SW2SSLBIS for SW2DSP1 (EP5), EP5 DSLBIS, EP5 Upstream link)) + + * Min(SW 3 Upstream Link to RP3 BW, + * Min(SW3SSLBIS for SW3DSP0 (EP6), EP6 DSLBIS, EP6 Upstream Link) + + * Min(SW3SSLBIS for SW3DSP1 (EP7), EP7 DSLBIS, EP7 Upstream link)))) + */ +void cxl_region_shared_upstream_perf_update(struct cxl_region *cxlr) +{ + struct xarray *usp_xa, *iter_xa, *working_xa; + int rc; + + lockdep_assert_held(&cxl_dpa_rwsem); + + usp_xa = kzalloc(sizeof(*usp_xa), GFP_KERNEL); + if (!usp_xa) + return; + + xa_init(usp_xa); + + /* + * Collect aggregated endpoint bandwidth and store the bandwidth in + * an xarray indexed by the upstream port of the switch. The bandwidth + * is aggregated per switch. Each endpoint consists of the minumum of + * bandwidth from DSLBIS from the endpoint CDAT, the endpoint upstream + * link bandwidth, and the bandwidth from the SSLBIS of the switch + * CDAT for the downstream port that's associated with the endpoint. + */ + for (int i = 0; i < cxlr->params.nr_targets; i++) { + struct cxl_endpoint_decoder *cxled = cxlr->params.targets[i]; + + rc = cxl_endpoint_gather_coordinates(cxlr, cxled, usp_xa); + if (rc) { + free_perf_xa(usp_xa); + return; + } + } + + /* + * Iterate through the components in the xarray and aggregate any + * component that share the same upstream switch. The iteration + * takes consideration of multi-level switch hierachy. + * + * When cxl_switch_iterate_coordinates() detect the next level + * upstream is a root port, it updates the bandwidth in the + * xarray by taking the min of the provided bandwidth and + * the bandwidth from the generic port. The function + * returns NULL to indicate that the input xarray has been + * updated. + */ + iter_xa = usp_xa; + usp_xa = NULL; + do { + working_xa = cxl_switch_iterate_coordinates(iter_xa); + if (IS_ERR(working_xa)) { + free_perf_xa(iter_xa); + return; + } + if (working_xa) { + free_perf_xa(iter_xa); + iter_xa = working_xa; + } + } while (working_xa); + + /* + * Aggregate the bandwidths in the xarray and update the region + * bandwidths with the newly calculated bandwidths. + */ + cxl_region_update_access_coordinate(cxlr, iter_xa); + free_perf_xa(iter_xa); +} + +void cxl_region_perf_data_calculate(struct cxl_region *cxlr, + struct cxl_endpoint_decoder *cxled) +{ + struct cxl_memdev *cxlmd = cxled_to_memdev(cxled); + struct cxl_dev_state *cxlds = cxlmd->cxlds; + struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds); + struct cxl_dpa_perf *perf; + + perf = cxl_memdev_get_dpa_perf(mds, cxlr->mode); + if (IS_ERR(perf)) + return; + + lockdep_assert_held(&cxl_dpa_rwsem); + + if (!dpa_perf_contains(perf, cxled->dpa_res)) return; for (int i = 0; i < ACCESS_COORDINATE_MAX; i++) { diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h index 625394486459..c72a7b9f5e21 100644 --- a/drivers/cxl/core/core.h +++ b/drivers/cxl/core/core.h @@ -103,9 +103,11 @@ enum cxl_poison_trace_type { }; long cxl_pci_get_latency(struct pci_dev *pdev); - +int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c); int cxl_update_hmat_access_coordinates(int nid, struct cxl_region *cxlr, enum access_coordinate_class access); bool cxl_need_node_perf_attrs_update(int nid); +int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port, + struct access_coordinate *c); #endif /* __CXL_CORE_H__ */ diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 8567dd11eaac..490c64cda56f 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -1074,3 +1074,24 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port) __cxl_endpoint_decoder_reset_detected); } EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_reset_detected, CXL); + +int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c) +{ + int speed, bw; + u16 lnksta; + u32 width; + + speed = pcie_link_speed_mbps(pdev); + if (speed < 0) + return -ENXIO; + speed /= BITS_PER_BYTE; + + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnksta); + width = FIELD_GET(PCI_EXP_LNKSTA_NLW, lnksta); + bw = speed * width; + + for (int i = 0; i < ACCESS_COORDINATE_MAX; i++) + c[i].read_bandwidth = c[i].write_bandwidth = bw; + + return 0; +} diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c index 887ed6e358fb..2c7509a9a943 100644 --- a/drivers/cxl/core/port.c +++ b/drivers/cxl/core/port.c @@ -2259,6 +2259,32 @@ int cxl_endpoint_get_perf_coordinates(struct cxl_port *port, } EXPORT_SYMBOL_NS_GPL(cxl_endpoint_get_perf_coordinates, CXL); +int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port, + struct access_coordinate *c) +{ + struct cxl_dport *dport; + struct cxl_port *iter; + + iter = port; + dport = port->parent_dport; + iter = to_cxl_port(iter->dev.parent); + + if (parent_port_is_cxl_root(iter)) + return -ENODEV; + + if (!coordinates_valid(dport->coord)) { + dev_warn(dport->dport_dev, "XXX %s invalid coords\n", __func__); + return -EINVAL; + } + + for (int i = 0; i < ACCESS_COORDINATE_MAX; i++) { + c[i].read_bandwidth = dport->coord[i].read_bandwidth; + c[i].write_bandwidth = dport->coord[i].write_bandwidth; + } + + return 0; +} + /* for user tooling to ensure port disable work has completed */ static ssize_t flush_store(const struct bus_type *bus, const char *buf, size_t count) { diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 00a9f0eef8dd..be7df4874951 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -3281,6 +3281,10 @@ static int cxl_region_probe(struct device *dev) goto out; } + down_read(&cxl_dpa_rwsem); + cxl_region_shared_upstream_perf_update(cxlr); + up_read(&cxl_dpa_rwsem); + /* * From this point on any path that changes the region's state away from * CXL_CONFIG_COMMIT is also responsible for releasing the driver. diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 603c0120cff8..34e83a6c55a1 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -891,6 +891,7 @@ int cxl_endpoint_get_perf_coordinates(struct cxl_port *port, struct access_coordinate *coord); void cxl_region_perf_data_calculate(struct cxl_region *cxlr, struct cxl_endpoint_decoder *cxled); +void cxl_region_shared_upstream_perf_update(struct cxl_region *cxlr); void cxl_memdev_update_perf(struct cxl_memdev *cxlmd); -- 2.45.0
