Date: Fri, 03 Aug 2018 16:25:03 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230334] busdma(9) is missing bus_dmamap_sync_range() Message-ID: <bug-230334-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230334 Bug ID: 230334 Summary: busdma(9) is missing bus_dmamap_sync_range() Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: jhibbits@FreeBSD.org bus_dmamap_sync(9) syncs the entire page range in a mapping, which can be very costly if only a small range is needed. Some drivers, perhaps many, share DMA maps for multiple queues or entries, and only need to update one segment. Instead of syncing the full map, there should be a way to sync only the updated range. This is mentioned in https://reviews.freebsd.org/D16570 regarding NVMe performance implications, and in https://reviews.freebsd.org/D16517 as missing for sound buffers. -- You are receiving this mail because: You are the assignee for the bug.
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