On 14/07/15 15:12, Alexey Brodkin wrote:
> Hi Adrian,
>
> Just noticed that starting from Linux v4.2-rc1 "perf record"
> doesn't work on ARC. That's what I see:
> ------------>8------------
> # perf record ls -la
> Cannot use AUX area tracing mmaps
> failed to mmap with 38 (Function not implemented)
> ------------>8------------
>
> I believe that happens because by default auxtrace is enabled
> (NO_AUXTRACE=0) and so auxtrace_mmap__mmap() from
> "tools/perf/util/auxtrace.c" gets compiled in and following
> check fails:
> ------------>8------------
> #if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
> pr_err("Cannot use AUX area tracing mmaps\n");
> return -1;
> #endif
> ------------>8------------
>
> Unfortunately we don't have __sync_val_compare_and_swap()
> in our current toolchain. And ARC as of today is 32-bit architecture.
>
> Now if I pass NO_AUXTRACE=1 in perf building command then everything
> works as expected.
>
> So I'm wondering what would be the best way to get perf properly
> working for ARC (at least) and probably other architecture/toolchain
> combos?
>
> I see at least 2 options:
>
> [1] Add feature check for BITS_PER_LONG. And then if
> "BITS_PER_LONG != 32 & HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT"
> automatically set "NO_AUXTRACE=1" on building perf.
>
> [2] By default enable auxtrace only on selected architectures.
> For example Intel 64-bit and maybe others who really capable of
> running auxtrace (and may make use of it).
>
> Any suggestions are much appreciated.
>
> Just in case that's my back-trace to auxtrace_mmap__mmap():
> ------------>8------------
> #0 auxtrace_mmap__mmap (mm=0x11a1a44, mp=0x5fa468c0, userpg=0x2021e000, fd=4)
> at util/auxtrace.c:57
> #1 0x0005d3b0 in __perf_evlist__mmap (evlist=0x11a0f30, evlist=0x11a0f30,
> fd=4, mp=0x5fa468b8, idx=0) at util/evlist.c:838
> #2 perf_evlist__mmap_per_evsel (evlist=evlist@entry=0x11a0f30,
> idx=idx@entry=0, mp=mp@entry=0x5fa468b8, cpu=cpu@entry=0,
> thread=thread@entry=0, output=output@entry=0x5fa468b4) at util/evlist.c:861
> #3 0x0005de1e in perf_evlist__mmap_per_cpu (mp=0x5fa468b8, evlist=0x11a0f30)
> at util/evlist.c:910
> #4 perf_evlist__mmap_ex (evlist=0x11a0f30, evlist@entry=0x0,
> pages=<optimized out>, overwrite=overwrite@entry=false, auxtrace_pages=0,
> auxtrace_overwrite=<optimized out>) at util/evlist.c:1095
> #5 0x0001e906 in record__open (rec=0xf11a0 <record>) at builtin-record.c:305
> #6 __cmd_record (rec=0xf11a0 <record>, argv=<optimized out>,
> argc=<optimized out>) at builtin-record.c:519
> #7 cmd_record (argc=<optimized out>, argv=<optimized out>,
> prefix=<optimized out>) at builtin-record.c:1168
> #8 0x00053758 in run_builtin (p=p@entry=0xf2938 <commands+72>,
> argc=argc@entry=2, argv=argv@entry=0x11a1730) at perf.c:370
> #9 0x00053f10 in handle_internal_command (argv=0x11a1730, argc=2)
> at perf.c:429
> #10 run_argv (argv=0x5fa47c70, argcp=0x5fa47c74) at perf.c:473
> #11 main (argc=2, argv=0x5fa47d98) at perf.c:588
> ------------>8------------
>
How about this:
From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Date: Tue, 14 Jul 2015 15:32:41 +0300
Subject: [PATCH] perf tools: Fix misplaced check for
HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT
Move the checking for HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT
for AUX area mmaps until after checking if such mmaps are
used anyway.
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/auxtrace.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
index 7e7405c9b936..83d9dd96fe08 100644
--- a/tools/perf/util/auxtrace.c
+++ b/tools/perf/util/auxtrace.c
@@ -53,11 +53,6 @@ int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
{
struct perf_event_mmap_page *pc = userpg;
-#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
- pr_err("Cannot use AUX area tracing mmaps\n");
- return -1;
-#endif
-
WARN_ONCE(mm->base, "Uninitialized auxtrace_mmap\n");
mm->userpg = userpg;
@@ -73,6 +68,11 @@ int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
return 0;
}
+#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
+ pr_err("Cannot use AUX area tracing mmaps\n");
+ return -1;
+#endif
+
pc->aux_offset = mp->offset;
pc->aux_size = mp->len;
--
1.9.1
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