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  1. 16 May, 2012 4 commits
    • Steven Rostedt's avatar
      ring-buffer: Add integrity check at end of iter read · 659f451f
      Steven Rostedt authored 
      There use to be ring buffer integrity checks after updating the
size of the ring buffer. But now that the ring buffer can modify
the size while the system is running, the integrity checks were
removed, as they require the ring buffer to be disabed to perform
the check.

Move the integrity check to the reading of the ring buffer via the
iterator reads (the "trace" file). As reading via an iterator requires
disabling the ring buffer, it is a perfect place to have it.

If the ring buffer happens to be disabled when updating the size,
we still perform the integrity check.

Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      659f451f
    • Vaibhav Nagarnaik's avatar
      ring-buffer: Make addition of pages in ring buffer atomic · 5040b4b7
      Vaibhav Nagarnaik authored 
      This patch adds the capability to add new pages to a ring buffer
atomically while write operations are going on. This makes it possible
to expand the ring buffer size without reinitializing the ring buffer.

The new pages are attached between the head page and its previous page.

Link: http://lkml.kernel.org/r/1336096792-25373-2-git-send-email-vnagarnaik@google.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: default avatarVaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      5040b4b7
    • Vaibhav Nagarnaik's avatar
      ring-buffer: Make removal of ring buffer pages atomic · 83f40318
      Vaibhav Nagarnaik authored 
      This patch adds the capability to remove pages from a ring buffer
without destroying any existing data in it.

This is done by removing the pages after the tail page. This makes sure
that first all the empty pages in the ring buffer are removed. If the
head page is one in the list of pages to be removed, then the page after
the removed ones is made the head page. This removes the oldest data
from the ring buffer and keeps the latest data around to be read.

To do this in a non-racey manner, tracing is stopped for a very short
time while the pages to be removed are identified and unlinked from the
ring buffer. The pages are freed after the tracing is restarted to
minimize the time needed to stop tracing.

The context in which the pages from the per-cpu ring buffer are removed
runs on the respective CPU. This minimizes the events not traced to only
NMI trace contexts.

Link: http://lkml.kernel.org/r/1336096792-25373-1-git-send-email-vnagarnaik@google.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: default avatarVaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      83f40318
    • Steven Rostedt's avatar
      tracing: Clean up tracing_mark_write() · 6edb2a8a
      Steven Rostedt authored 
      On gcc 4.5 the function tracing_mark_write() would give a warning
of page2 being uninitialized. This is due to a bug in gcc because
the logic prevents page2 from being used uninitialized, and
gcc 4.6+ does not complain (correctly).

Instead of adding a "unitialized" around page2, which could show
a bug later on, I combined page1 and page2 into an array map_pages[].
This binds the two and the two are modified according to nr_pages
(what gcc 4.5 seems to ignore). This no longer gives a warning with
gcc 4.5 nor with gcc 4.6.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      6edb2a8a
  3. 14 May, 2012 2 commits
  5. 12 May, 2012 5 commits
  7. 11 May, 2012 4 commits
  9. 10 May, 2012 1 commit
  11. 09 May, 2012 23 commits
  13. 08 May, 2012 1 commit
    • Ingo Molnar's avatar
      Merge branch 'perf/annotate' of... · 149936a0
      Ingo Molnar authored 
      Merge branch 'perf/annotate' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Perf annotate browser improvements:

 - Get back the line separating the overheads from the disassembly, requested by
   Peter Zijlstra, Linus agreed now that it is a solid line and more column real
   state was harvested. Also it has the jump->arrow lines separated from it by
   the address/jump target column.

 - Don't change asm line color when toggling source code view. Requested by
   Peter Zijlstra.

Current snapshot:

 avtab_search_node
        │      push   %rbp
        │      mov    %rsp,%rbp
        │    → callq  mcount
        │      movzwl 0x6(%rsi),%edx
        │      and    $0x7fff,%dx
        │      test   %rdi,%rdi
        │    ↓ jne    20
   0.42 │17:┌─→xor    %eax,%eax
        │19:│  leaveq
   0.42 │   │← retq
        │   │  nopl   0x0(%rax,%rax,1)
        │20:│  mov    (%rdi),%rax
   0.08 │   │  test   %rax,%rax
        │   └──je     17
        │      movzwl (%rsi),%ecx
        │      movzwl 0x2(%rsi),%r9d
        │      movzwl 0x4(%rsi),%r8d
        │      movzwl %cx,%esi
        │      movzwl %r9w,%r10d
        │      shl    $0x9,%esi
        │      lea    (%rsi,%r10,4),%esi
        │      lea    (%r8,%rsi,1),%esi
        │      and    0x10(%rdi),%si
        │      movzwl %si,%esi
        │      mov    (%rax,%rsi,8),%rax
   1.01 │      test   %rax,%rax
        │    ↑ je     19
        │      nopw   0x0(%rax,%rax,1)
   3.19 │60:   cmp    %cx,(%rax)
        │    ↓ jne    7e
   0.08 │      cmp    %r9w,0x2(%rax)
        │    ↓ jne    7e
        │      cmp    %r8w,0x4(%rax)
        │    ↓ jne    79
        │      test   %dx,0x6(%rax)
        │    ↑ jne    19
        │79:   cmp    %r8w,0x4(%rax)
  83.45 │7e: ↑ ja     17
   3.36 │      mov    0x10(%rax),%rax
   7.98 │      test   %rax,%rax
        │    ↑ jne    60
        │      leaveq
        │    ← retq
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      149936a0
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