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* [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase @ 2021-06-14 12:44 mhov at undo dot io 2021-06-14 12:45 ` [Bug gdb/27979] " mhov at undo dot io ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: mhov at undo dot io @ 2021-06-14 12:44 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=27979 Bug ID: 27979 Summary: Performance regression of ~10% in conditional breakpoint testcase Product: gdb Version: 10.1 Status: UNCONFIRMED Severity: normal Priority: P2 Component: gdb Assignee: unassigned at sourceware dot org Reporter: mhov at undo dot io Target Milestone: --- Created attachment 13491 --> https://sourceware.org/bugzilla/attachment.cgi?id=13491&action=edit reproducer program There seems to be a performance regression from 9.2 to 10.2 that is observable in the time to run the following command on the attached reproducer program. This has been used to benchmark the performance of conditional breakpoints. $ gcc --version gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0 $ gcc -g repro.c $ ./gdb --batch --ex "b foo if bar==0x7ffffff" --ex "run" --args ./a.out Also attached is a log from the libera.chat #gdb channel where this regression was discussed. As can be seen in the attached chat log, bisection by Simon suggests that this commit is to blame: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1009d92fc621bc4d017029b90a5bfab16e17fde5 I'm not currently in a position to delve deeper into this, so I'm posting here in case anyone wants to pick it up. -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug gdb/27979] Performance regression of ~10% in conditional breakpoint testcase 2021-06-14 12:44 [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase mhov at undo dot io @ 2021-06-14 12:45 ` mhov at undo dot io 2021-06-14 12:47 ` mhov at undo dot io ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: mhov at undo dot io @ 2021-06-14 12:45 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=27979 --- Comment #1 from Magne Hov <mhov at undo dot io> --- Created attachment 13492 --> https://sourceware.org/bugzilla/attachment.cgi?id=13492&action=edit #gdb chatlog Attached chatlog -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug gdb/27979] Performance regression of ~10% in conditional breakpoint testcase 2021-06-14 12:44 [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase mhov at undo dot io 2021-06-14 12:45 ` [Bug gdb/27979] " mhov at undo dot io @ 2021-06-14 12:47 ` mhov at undo dot io 2021-06-14 12:58 ` simark at simark dot ca 2021-06-14 15:21 ` ssbssa at sourceware dot org 3 siblings, 0 replies; 5+ messages in thread From: mhov at undo dot io @ 2021-06-14 12:47 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=27979 Magne Hov <mhov at undo dot io> changed: What |Removed |Added ---------------------------------------------------------------------------- Version|10.1 |HEAD -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug gdb/27979] Performance regression of ~10% in conditional breakpoint testcase 2021-06-14 12:44 [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase mhov at undo dot io 2021-06-14 12:45 ` [Bug gdb/27979] " mhov at undo dot io 2021-06-14 12:47 ` mhov at undo dot io @ 2021-06-14 12:58 ` simark at simark dot ca 2021-06-14 15:21 ` ssbssa at sourceware dot org 3 siblings, 0 replies; 5+ messages in thread From: simark at simark dot ca @ 2021-06-14 12:58 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=27979 Simon Marchi <simark at simark dot ca> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |simark at simark dot ca --- Comment #2 from Simon Marchi <simark at simark dot ca> --- Things to investigate: - We do a lot of work finding tailcalls even though no tailcalls are involved the test case. Is there a way we can do less work in this case? - On the fast path, while looking for tailcalls, a NO_ENTRY_VALUE_ERROR exception is thrown. It's probably not good to rely on exceptions being thrown in the normal path of the program, maybe try to change that with functions returning nullptr if they don't find anything. -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug gdb/27979] Performance regression of ~10% in conditional breakpoint testcase 2021-06-14 12:44 [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase mhov at undo dot io ` (2 preceding siblings ...) 2021-06-14 12:58 ` simark at simark dot ca @ 2021-06-14 15:21 ` ssbssa at sourceware dot org 3 siblings, 0 replies; 5+ messages in thread From: ssbssa at sourceware dot org @ 2021-06-14 15:21 UTC (permalink / raw) To: gdb-prs https://sourceware.org/bugzilla/show_bug.cgi?id=27979 Hannes Domani <ssbssa at sourceware dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ssbssa at sourceware dot org -- You are receiving this mail because: You are on the CC list for the bug. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-06-14 15:21 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-06-14 12:44 [Bug gdb/27979] New: Performance regression of ~10% in conditional breakpoint testcase mhov at undo dot io 2021-06-14 12:45 ` [Bug gdb/27979] " mhov at undo dot io 2021-06-14 12:47 ` mhov at undo dot io 2021-06-14 12:58 ` simark at simark dot ca 2021-06-14 15:21 ` ssbssa at sourceware dot org
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