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Date: Wed, 4 May 2016 18:01:52 +0100
From: Edward Cree <ecree@...arflare.com>
To: <linux-net-drivers@...arflare.com>,
netdev <netdev@...r.kernel.org>,
David Miller <davem@...emloft.net>
Subject: [PATCH net-next 1/2] sfc: Support setting rss_cpus to 'cores',
'packages' or 'hyperthreads'
These settings autoconfigure the number of RSS channels to match the number of
CPUs present.
Signed-off-by: Edward Cree <ecree@...arflare.com>
---
drivers/net/ethernet/sfc/efx.c | 143 ++++++++++++++++++++++++++++++++---------
1 file changed, 113 insertions(+), 30 deletions(-)
diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 0705ec86..e6fdf35 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -22,6 +22,7 @@
#include <linux/gfp.h>
#include <linux/aer.h>
#include <linux/interrupt.h>
+#include <xen/xen.h>
#include "net_driver.h"
#include "efx.h"
#include "nic.h"
@@ -161,16 +162,19 @@ static unsigned int tx_irq_mod_usec = 150;
*/
static unsigned int interrupt_mode;
-/* This is the requested number of CPUs to use for Receive-Side Scaling (RSS),
- * i.e. the number of CPUs among which we may distribute simultaneous
- * interrupt handling.
+/* This is the requested number of CPUs to use for Receive-Side Scaling
+ * (RSS), i.e. the number of CPUs among which we may distribute
+ * simultaneous interrupt handling. Or alternatively it may be set to
+ * "packages", "cores" or "hyperthreads" to get one receive channel per
+ * package, core or hyperthread. The default is "cores".
*
- * Cards without MSI-X will only target one CPU via legacy or MSI interrupt.
- * The default (0) means to assign an interrupt to each core.
+ * Systems without MSI-X will only target one CPU via legacy or MSI
+ * interrupt.
*/
-static unsigned int rss_cpus;
-module_param(rss_cpus, uint, 0444);
-MODULE_PARM_DESC(rss_cpus, "Number of CPUs to use for Receive-Side Scaling");
+static char *rss_cpus;
+module_param(rss_cpus, charp, 0444);
+MODULE_PARM_DESC(rss_cpus, "Number of CPUs to use for Receive-Side Scaling, "
+ "or 'packages', 'cores' or 'hyperthreads'");
static bool phy_flash_cfg;
module_param(phy_flash_cfg, bool, 0644);
@@ -1324,51 +1328,130 @@ void efx_set_default_rx_indir_table(struct efx_nic *efx)
ethtool_rxfh_indir_default(i, efx->rss_spread);
}
-static unsigned int efx_wanted_parallelism(struct efx_nic *efx)
+/* Count the number of unique packages in the given cpumask */
+static unsigned int efx_num_packages(const cpumask_t *in)
{
- cpumask_var_t thread_mask;
+ cpumask_var_t core_mask;
+ unsigned int count;
+ int cpu, cpu2;
+
+ if (unlikely(!zalloc_cpumask_var(&core_mask, GFP_KERNEL))) {
+ pr_warn("sfc: RSS disabled due to allocation failure\n");
+ return 1;
+ }
+
+ count = 0;
+ for_each_cpu(cpu, in) {
+ if (!cpumask_test_cpu(cpu, core_mask)) {
+ ++count;
+
+ /* Treat each numa node as a seperate package */
+ for_each_cpu(cpu2, topology_core_cpumask(cpu)) {
+ if (cpu_to_node(cpu) == cpu_to_node(cpu2))
+ cpumask_set_cpu(cpu2, core_mask);
+ }
+ }
+ }
+
+ free_cpumask_var(core_mask);
+
+ return count;
+}
+
+/* Count the number of unique cores in the given cpumask */
+static unsigned int efx_num_cores(const cpumask_t *in)
+{
+ cpumask_var_t core_mask;
unsigned int count;
int cpu;
- if (rss_cpus) {
- count = rss_cpus;
- } else {
- if (unlikely(!zalloc_cpumask_var(&thread_mask, GFP_KERNEL))) {
- netif_warn(efx, probe, efx->net_dev,
- "RSS disabled due to allocation failure\n");
- return 1;
+ if (unlikely(!zalloc_cpumask_var(&core_mask, GFP_KERNEL))) {
+ pr_warn("sfc: RSS disabled due to allocation failure\n");
+ return 1;
+ }
+
+ count = 0;
+ for_each_cpu(cpu, in) {
+ if (!cpumask_test_cpu(cpu, core_mask)) {
+ ++count;
+ cpumask_or(core_mask, core_mask,
+ topology_sibling_cpumask(cpu));
}
+ }
- count = 0;
- for_each_online_cpu(cpu) {
- if (!cpumask_test_cpu(cpu, thread_mask)) {
- ++count;
- cpumask_or(thread_mask, thread_mask,
- topology_sibling_cpumask(cpu));
- }
+ free_cpumask_var(core_mask);
+ return count;
+}
+
+static unsigned int efx_wanted_parallelism(struct efx_nic *efx)
+{
+ struct net_device *net_dev = efx->net_dev;
+ unsigned int n_rxq;
+
+ if (rss_cpus == NULL) {
+ /* default to 'cores' */
+ goto cores;
+ } else if (strcmp(rss_cpus, "packages") == 0) {
+ if (xen_domain()) {
+ netif_warn(efx, drv, net_dev,
+ "Unable to determine CPU topology on Xen reliably. Using 4 rss channels.\n");
+ n_rxq = 4;
+ } else {
+ netif_dbg(efx, drv, net_dev,
+ "using efx_num_packages()\n");
+ n_rxq = efx_num_packages(cpu_online_mask);
+ /* Create two RSS queues even with a single package */
+ if (n_rxq == 1)
+ n_rxq = 2;
}
+ } else if (strcmp(rss_cpus, "cores") == 0) {
+cores:
+ if (xen_domain()) {
+ netif_warn(efx, drv, net_dev,
+ "Unable to determine CPU topology on Xen reliably. Assuming hyperthreading enabled.\n");
+ n_rxq = max_t(int, 1, num_online_cpus() / 2);
+ } else {
+ netif_dbg(efx, drv, net_dev,
+ "using efx_num_cores()\n");
+ n_rxq = efx_num_cores(cpu_online_mask);
+ }
+ } else if (strcmp(rss_cpus, "hyperthreads") == 0) {
+ n_rxq = num_online_cpus();
+ } else if (sscanf(rss_cpus, "%u", &n_rxq) == 1 && n_rxq > 0) {
+ /* nothing to do */
+ } else {
+ netif_err(efx, drv, net_dev,
+ "Bad value for module parameter rss_cpus='%s'\n",
+ rss_cpus);
+ /* default to 'cores' */
+ goto cores;
+ }
- free_cpumask_var(thread_mask);
+ if (n_rxq > EFX_MAX_RX_QUEUES) {
+ netif_warn(efx, drv, net_dev,
+ "Reducing number of rss channels from %u to %u.\n",
+ n_rxq, EFX_MAX_RX_QUEUES);
+ n_rxq = EFX_MAX_RX_QUEUES;
}
+#ifdef CONFIG_SFC_SRIOV
/* If RSS is requested for the PF *and* VFs then we can't write RSS
* table entries that are inaccessible to VFs
*/
-#ifdef CONFIG_SFC_SRIOV
if (efx->type->sriov_wanted) {
if (efx->type->sriov_wanted(efx) && efx_vf_size(efx) > 1 &&
- count > efx_vf_size(efx)) {
+ n_rxq > efx_vf_size(efx)) {
netif_warn(efx, probe, efx->net_dev,
"Reducing number of RSS channels from %u to %u for "
"VF support. Increase vf-msix-limit to use more "
"channels on the PF.\n",
- count, efx_vf_size(efx));
- count = efx_vf_size(efx);
+ n_rxq, efx_vf_size(efx));
+ n_rxq = efx_vf_size(efx);
}
}
#endif
- return count;
+ return n_rxq;
}
/* Probe the number and type of interrupts we are able to obtain, and
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