Commit 4fe61bff authored Jan 13, 2023 by Babu Moger Committed by Borislav Petkov (AMD) Jan 23, 2023

x86/resctrl: Add interface to write mbm_local_bytes_config



The event configuration for mbm_local_bytes can be changed by the
user by writing to the configuration file
/sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config.

The event configuration settings are domain specific and will affect all
the CPUs in the domain.

Following are the types of events supported:

  ====  ===========================================================
  Bits   Description
  ====  ===========================================================
  6      Dirty Victims from the QOS domain to all types of memory
  5      Reads to slow memory in the non-local NUMA domain
  4      Reads to slow memory in the local NUMA domain
  3      Non-temporal writes to non-local NUMA domain
  2      Non-temporal writes to local NUMA domain
  1      Reads to memory in the non-local NUMA domain
  0      Reads to memory in the local NUMA domain
  ====  ===========================================================

For example, to change the mbm_local_bytes_config to count all the non-temporal
writes on domain 0, the bits 2 and 3 needs to be set which is 1100b (in hex
0xc).
Run the command:

  $echo  0=0xc > /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config

To change the mbm_local_bytes to count only reads to local NUMA domain 1,
the bit 0 needs to be set which 1b (in hex 0x1). Run the command:

  $echo  1=0x1 > /sys/fs/resctrl/info/L3_MON/mbm_local_bytes_config

Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/r/20230113152039.770054-13-babu.moger@amd.com

parent 92bd5a13

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+26 −1

Original line number	Diff line number	Diff line
		@@ -1638,6 +1638,30 @@ static ssize_t mbm_total_bytes_config_write(struct kernfs_open_file *of,
		return ret ?: nbytes;
		}

		static ssize_t mbm_local_bytes_config_write(struct kernfs_open_file *of,
		char *buf, size_t nbytes,
		loff_t off)
		{
		struct rdt_resource *r = of->kn->parent->priv;
		int ret;

		/* Valid input requires a trailing newline */
		if (nbytes == 0 \|\| buf[nbytes - 1] != '\n')
		return -EINVAL;

		mutex_lock(&rdtgroup_mutex);

		rdt_last_cmd_clear();

		buf[nbytes - 1] = '\0';

		ret = mon_config_write(r, buf, QOS_L3_MBM_LOCAL_EVENT_ID);

		mutex_unlock(&rdtgroup_mutex);

		return ret ?: nbytes;
		}

		/* rdtgroup information files for one cache resource. */
		static struct rftype res_common_files[] = {
		{
		@@ -1745,9 +1769,10 @@ static struct rftype res_common_files[] = {
		},
		{
		.name = "mbm_local_bytes_config",
		.mode = 0444,
		.mode = 0644,
		.kf_ops = &rdtgroup_kf_single_ops,
		.seq_show = mbm_local_bytes_config_show,
		.write = mbm_local_bytes_config_write,
		},
		{
		.name = "cpus",