Bug 4226 - new libunwind bindings test-ptrace-mapper very slow.
Summary: new libunwind bindings test-ptrace-mapper very slow.
Status: NEW
Alias: None
Product: frysk
Classification: Unclassified
Component: general (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Unassigned
URL:
Keywords:
Depends on:
Blocks: 3076
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Reported: 2007-03-20 21:38 UTC by Nurdin Premji
Modified: 2016-05-16 18:46 UTC (History)
0 users

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Attachments
libunwind 20070224 straced. (172.97 KB, application/x-bzip)
2007-03-20 21:48 UTC, Nurdin Premji 		Details
libunwind 0.98.5 straced. (34.78 KB, application/x-bzip)
2007-03-20 21:50 UTC, Nurdin Premji 		Details
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Description Nurdin Premji 2007-03-20 21:38:37 UTC
Comment 1 Nurdin Premji 2007-03-20 21:48:24 UTC 
Created attachment 1637 [details]
libunwind 20070224 straced.
Comment 2 Nurdin Premji 2007-03-20 21:50:50 UTC 
Created attachment 1638 [details]
libunwind 0.98.5 straced.
Comment 3 Nurdin Premji 2007-03-20 22:49:06 UTC 
It seems as though this bug has to do with caching. The logs show that reads are
done when no ptrace-continue has occurred and the maps should still be valid.

<cagney> ptrace(PTRACE_PEEKUSER, 24688, 4*EIP, [0x56c402]) = 0
<cagney> open("/proc/24688/maps", O_RDONLY)      = 3
<cagney> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f15000
<cagney> read(3, "0056c000-0056d000 r-xp 0056c000 "..., 4096) = 4060
<cagney> read(3, "b7fb6000-b7fb7000 -w-p b7fb6000 "..., 4096) = 1574
<cagney> read(3, "", 4096)                       = 0
<cagney> close(3)                                = 0
<cagney> munmap(0xb7f15000, 4096)                = 0
<cagney> rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1], [], 8) = 0
<cagney> open("/proc/24688/maps", O_RDONLY)      = 3
<cagney> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0xb7f15000
<cagney> read(3, "0056c000-0056d000 r-xp 0056c000 "..., 4096) = 4060
<cagney> read(3, "b0aec000-b0aed000 -w-p b0aec000 "..., 4096) = 4059
Comment 4 Nurdin Premji 2007-03-20 23:03:40 UTC 
upstream bug:
https://savannah.nongnu.org/bugs/index.php?19365