linux/drivers/infiniband/hw/hfi1/aspm.h

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/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
/*
* Copyright(c) 2015-2017 Intel Corporation.
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
*/
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
#ifndef _ASPM_H
#define _ASPM_H
#include "hfi.h"
extern uint aspm_mode;
enum aspm_mode {
ASPM_MODE_DISABLED = 0, /* ASPM always disabled, performance mode */
ASPM_MODE_ENABLED = 1, /* ASPM always enabled, power saving mode */
ASPM_MODE_DYNAMIC = 2, /* ASPM enabled/disabled dynamically */
};
void aspm_init(struct hfi1_devdata *dd);
void aspm_exit(struct hfi1_devdata *dd);
void aspm_hw_disable_l1(struct hfi1_devdata *dd);
void __aspm_ctx_disable(struct hfi1_ctxtdata *rcd);
void aspm_disable_all(struct hfi1_devdata *dd);
void aspm_enable_all(struct hfi1_devdata *dd);
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
static inline void aspm_ctx_disable(struct hfi1_ctxtdata *rcd)
{
/* Quickest exit for minimum impact */
if (likely(!rcd->aspm_intr_supported))
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
return;
__aspm_ctx_disable(rcd);
staging/rdma/hfi1: Add support for enabling/disabling PCIe ASPM hfi1 HW has a high PCIe ASPM L1 exit latency and also advertises an acceptable latency less than actual ASPM latencies. Additional mechanisms than those provided by BIOS/OS are therefore required to enable/disable ASPM for hfi1 to provide acceptable power/performance trade offs. This patch adds this support. By means of a module parameter ASPM can be either (a) always enabled (power save mode) (b) always disabled (performance mode) (c) enabled/disabled dynamically. The dynamic mode implements two heuristics to alleviate possible problems with high ASPM L1 exit latency. ASPM is normally enabled but is disabled if (a) there are any active user space PSM contexts, or (b) for verbs, ASPM is disabled as interrupt activity for a context starts to increase. A few more points about the verbs implementation. In order to reduce lock/cache contention between multiple verbs contexts, some processing is done at the context layer before contending for device layer locks. ASPM is disabled when two interrupts for a context happen within 1 millisec. A timer is scheduled which will re-enable ASPM after 1 second should the interrupt activity cease. Normally, every interrupt, or interrupt-pair should push the timer out further. However, since this might increase the processing load per interrupt, pushing the timer out is postponed for half a second. If after half a second we get two interrupts within 1 millisec the timer is pushed out by another second. Finally, the kernel ASPM API is not used in this patch. This is because this patch does several non-standard things as SW workarounds for HW issues. As mentioned above, it enables ASPM even when advertised actual latencies are greater than acceptable latencies. Also, whereas the kernel API only allows drivers to disable ASPM from driver probe, this patch enables/disables ASPM directly from interrupt context. Due to these reasons the kernel ASPM API was not used. Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-by: Dean Luick <dean.luick@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
2016-02-04 01:33:06 +03:00
}
#endif /* _ASPM_H */