performance: add low latency hint for exec queues #794
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When workloads submit compute kernels, it's required to keep low submission latency. Impact of submission overhead is significant in a burst model, when application submits short-running kernels continuously. Signed-off-by: Szymon Morek <szymon.morek@intel.com>
When workloads submit compute kernels, it's required to keep low submission latency. Impact of submission overhead is significant in a burst model, when application submits short-running kernels continuously. Signed-off-by: Szymon Morek <szymon.morek@intel.com>
intel-lab-lkp
pushed a commit
to intel-lab-lkp/linux
that referenced
this pull request
Jan 9, 2025
Allow user to provide a low latency hint per exec queue. When set,
KMD sends a hint to GuC which results in special handling for this
exec queue. SLPC will ramp the GT frequency aggressively every time
it switches to this exec queue.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to exec queues that set this bit during exec queue
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
UMD will indicate low latency hint with flag as mentioned below,
* struct drm_xe_exec_queue_create exec_queue_create = {
* .flags = DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT or 0
* .extensions = 0,
* .vm_id = vm,
* .num_bb_per_exec = 1,
* .num_eng_per_bb = 1,
* .instances = to_user_pointer(&instance),
* };
* ioctl(fd, DRM_IOCTL_XE_EXEC_QUEUE_CREATE, &exec_queue_create);
Link to UMD PR : intel/compute-runtime#794
Note: There is outstanding issue on guc side to be not able to switch to max
frequency as per strategy indicated by KMD, so for experminet/test result
hardcoding apporch was taken and passed to guc as policy. Effort on debugging
from guc side is going on in parallel.
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 is already planned for other hint(Szymon)
- Add motivation to description (Lucas)
Cc:dri-devel@lists.freedesktop.org
Cc:vinay.belgaumkar@intel.com
Cc:Michal Mrozek <michal.mrozek@intel.com>
Cc:Szymon Morek <szymon.morek@intel.com>
Cc:José Roberto de Souza <jose.souza@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
When workloads submit compute kernels, it's required to keep low submission latency. Impact of submission overhead is significant in a burst model, when application submits short-running kernels continuously. Signed-off-by: Szymon Morek <szymon.morek@intel.com>
intel-lab-lkp
pushed a commit
to intel-lab-lkp/linux
that referenced
this pull request
Jan 10, 2025
Allow user to provide a low latency hint per exec queue. When set,
KMD sends a hint to GuC which results in special handling for this
exec queue. SLPC will ramp the GT frequency aggressively every time
it switches to this exec queue.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to exec queues that set this bit during exec queue
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
UMD will indicate low latency hint with flag as mentioned below,
* struct drm_xe_exec_queue_create exec_queue_create = {
* .flags = DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT or 0
* .extensions = 0,
* .vm_id = vm,
* .num_bb_per_exec = 1,
* .num_eng_per_bb = 1,
* .instances = to_user_pointer(&instance),
* };
* ioctl(fd, DRM_IOCTL_XE_EXEC_QUEUE_CREATE, &exec_queue_create);
Link to UMD PR : intel/compute-runtime#794
Note: There is outstanding issue on guc side to be not able to switch to max
frequency as per strategy indicated by KMD, so for experminet/test result
hardcoding apporch was taken and passed to guc as policy. Effort on debugging
from guc side is going on in parallel.
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 is already planned for other hint(Szymon)
- Add motivation to description (Lucas)
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
When workloads submit compute kernels, it's required to keep low submission latency. Impact of submission overhead is significant in a burst model, when application submits short-running kernels continuously. Signed-off-by: Szymon Morek <szymon.morek@intel.com>
intel-lab-lkp
pushed a commit
to intel-lab-lkp/linux
that referenced
this pull request
Feb 12, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
UMD Compute PR : intel/compute-runtime#794
UMD Mesa PR : https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 is already planned for other hint(Szymon)
- Add motivation to description (Lucas)
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
intel-lab-lkp
pushed a commit
to intel-lab-lkp/linux
that referenced
this pull request
Feb 24, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
UMD Compute PR : intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250212121814.9947-1-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
intel-lab-lkp
pushed a commit
to intel-lab-lkp/linux
that referenced
this pull request
Mar 5, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
May 24, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Jun 14, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Jun 20, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Jul 25, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Aug 16, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Sep 20, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
lutzbichler
pushed a commit
to lutzbichler/drm-kmod
that referenced
this pull request
Sep 26, 2025
Allow user to provide a low latency hint. When set, KMD sends a hint
to GuC which results in special handling for that process. SLPC will
ramp the GT frequency aggressively every time it switches to this
process.
We need to enable the use of SLPC Compute strategy during init, but
it will apply only to processes that set this bit during process
creation.
Improvement with this approach as below:
Before,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 283.16 us
After,
:~$ NEOReadDebugKeys=1 EnableDirectSubmission=0 clpeak --kernel-latency
Platform: Intel(R) OpenCL Graphics
Device: Intel(R) Graphics [0xe20b]
Driver version : 24.52.0 (Linux x64)
Compute units : 160
Clock frequency : 2850 MHz
Kernel launch latency : 63.38 us
Compute PR: intel/compute-runtime#794
Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33214
IGT PR: https://patchwork.freedesktop.org/patch/639989/
V10(Lucas):
- Remove doc from drm-uapi.rst
v9(Vinay):
- remove extra line, align commit message
v8(Vinay):
- Add separate example for using low latency hint
v7(Jose):
- Update UMD PR
- applicable to all gpus
V6:
- init flags, remove redundant flags check (MAuld)
V5:
- Move uapi doc to documentation and GuC ABI specific change (Rodrigo)
- Modify logic to restrict exec queue flags (MAuld)
V4:
- To make it clear, dont use exec queue word (Vinay)
- Correct typo in description of flag (Jose/Vinay)
- rename set_strategy api and replace ctx with exec queue(Vinay)
- Start with 0th bit to indentify user flags (Jose)
V3:
- Conver user flag to kernel internal flag and use (Oak)
- Support query config for use to check kernel support (Jose)
- Dont need to take runtime pm (Vinay)
V2:
- DRM_XE_EXEC_QUEUE_LOW_LATENCY_HINT 1 planned for other hint(Szymon)
- Add motivation to description (Lucas)
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228070224.739295-2-tejas.upadhyay@intel.com
Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
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When workloads submit compute kernels, it's required
to keep low submission latency.
Impact of submission overhead is significant in a burst model,
when application submits short-running kernels continuously.
Signed-off-by: Szymon Morek szymon.morek@intel.com