Bug 53898
Summary: | kernel IO bottlenecks | ||||||||||||
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Product: | [Retired] Red Hat Linux | Reporter: | Sudhir Shetty <sudhir_shetty> | ||||||||||
Component: | kernel | Assignee: | Doug Ledford <dledford> | ||||||||||
Status: | CLOSED CURRENTRELEASE | QA Contact: | Brock Organ <borgan> | ||||||||||
Severity: | medium | Docs Contact: | |||||||||||
Priority: | medium | ||||||||||||
Version: | 7.2 | CC: | afom_m, dale_kaisner, john_hull, matt_domsch | ||||||||||
Target Milestone: | --- | Keywords: | FutureFeature | ||||||||||
Target Release: | --- | ||||||||||||
Hardware: | i386 | ||||||||||||
OS: | Linux | ||||||||||||
Whiteboard: | |||||||||||||
Fixed In Version: | Doc Type: | Enhancement | |||||||||||
Doc Text: | Story Points: | --- | |||||||||||
Clone Of: | Environment: | ||||||||||||
Last Closed: | 2002-02-13 20:22:38 UTC | Type: | --- | ||||||||||
Regression: | --- | Mount Type: | --- | ||||||||||
Documentation: | --- | CRM: | |||||||||||
Verified Versions: | Category: | --- | |||||||||||
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||||
Cloudforms Team: | --- | Target Upstream Version: | |||||||||||
Embargoed: | |||||||||||||
Attachments: |
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Description
Sudhir Shetty
2001-09-20 23:03:40 UTC
Created attachment 32298 [details]
Kernel profile
Created attachment 32299 [details]
Gunzip of test program
After doing some poking around inside the scsi layer, it appears that sd.c ends up calling b_end_io with the io_request_lock held. This results in any highmem bounce buffer copies being serialized for scsi requests. I don't think this needs the io_request_lock being split just yet, just bugfixing. In testing we have found several bugs in Jens's highmem nobounce patch, and we have made progress fixing. The io_request_lock stuff will take longer to fix because it requires more auditing. Created attachment 33661 [details]
kernelprofile
Created attachment 33662 [details]
iostat
FYI Attached are the kernelprofile and iostat logs for kernel 2.4.9-0.18smp. a) is dealt with b) is being worked on but is a longer-term because the changes are initially destabilizing and will require much more work not only to complete but also to stabilize. Our advanced server release is fixing most of these issues. How much is still visible in that beta ? (and with the latest kernel drop after that ?) This is closed based on feedback from Oracle (TPC-R benchmarking efforts). |