[userspace LL] disable VMH, increase heap - #11173
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VMH uses a hard-coded chunk configuration, which wastes SRAM. We can instead move to use vregions for large allocations, but while vregion use isn't sufficient, we temporarily increase the conventional heap. Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
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🟡 Changes recommended
SOF_ZEPHYR_VIRTUAL_HEAP_REGION_SIZE can still default non-zero when VIRTUAL_HEAP is disabled due to VIRTUAL_HEAP_EXTENDED defaulting to y, which undermines the intended SRAM savings.
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Pull request overview
This PR aims to reduce wasted SRAM caused by the VMH (virtual heap) hard-coded chunk configuration by disabling virtual heap usage (for PTL userspace-LL overlay) and temporarily increasing the conventional Zephyr heap size to compensate while vregion-based large allocations are still incomplete.
Changes:
- Increase the default
SOF_ZEPHYR_HEAP_SIZEforSOC_ACE30/SOC_ACE40. - Change
SOF_ZEPHYR_VIRTUAL_HEAP_REGION_SIZEdefaults to be non-zero only whenVIRTUAL_HEAPis enabled, otherwise default to0. - Disable
VIRTUAL_HEAPin the PTL userspace-LL overlay.
File summaries
| File | Description |
|---|---|
zephyr/Kconfig |
Adjust heap sizing defaults and virtual-heap-region sizing behavior. |
app/overlays/ptl/ll_userspace_overlay.conf |
Disable virtual heap in PTL userspace-LL overlay configuration. |
Review details
- Files reviewed: 2/2 changed files
- Comments generated: 2
- Review effort level: Lite
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| # TODO: needs some better solution to allocate | ||
| CONFIG_SOF_ZEPHYR_SYS_USER_HEAP_SIZE=0x80000 | ||
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| CONFIG_VIRTUAL_HEAP=n |
| default 0x140000 if VIRTUAL_HEAP_EXTENDED | ||
| default 0x100000 | ||
| default 0x100000 if VIRTUAL_HEAP | ||
| default 0x0 |
PR 11173: test resultsRun date: 2026-09-07 12:12 UTC Tested commit: d98531957849ecb8410324190a5df9b9e1eebd4c
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kv2019i
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kv2019i
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Commit msg could be more clear, but change itself is good.
| @@ -37,3 +37,5 @@ CONFIG_XRUN_NOTIFICATIONS_ENABLE=n | |||
| # enabled and uses the vmh allocation intended for KBP. | |||
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"vregion use isn't sufficient" is a bit hard to understand. Maybe something like "During the transition period when vregion is not yet used by all modules, we temporarily increase..."
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Fuzzer fails are known #11162 |
VMH uses a hard-coded chunk configuration, which wastes SRAM. We can instead move to use vregions for large allocations, but while vregion use isn't sufficient, we temporarily increase the conventional heap.