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perf symbols: Convert lseek + read to pread

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When dso_cache__read() is called, it reads data from the given offset
using lseek + normal read syscall.  It can be combined to a single pread
syscall.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1422518843-25818-40-git-send-email-namhyung@kernel.org
[ Fixed it up when cherry picking it from the multi threaded patchkit ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Namhyung Kim 2015-01-29 17:02:01 -03:00 committed by Arnaldo Carvalho de Melo
parent 42aa276f40
commit c52686f9f8
1 changed files with 1 additions and 5 deletions
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6
tools/perf/util/dso.c
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@ -532,12 +532,8 @@ dso_cache__read(struct dso *dso, u64 offset, u8 *data, ssize_t size)
break; break;
cache_offset = offset & DSO__DATA_CACHE_MASK; cache_offset = offset & DSO__DATA_CACHE_MASK;
ret = -EINVAL;
if (-1 == lseek(dso->data.fd, cache_offset, SEEK_SET)) ret = pread(dso->data.fd, cache->data, DSO__DATA_CACHE_SIZE, cache_offset);
break;
ret = read(dso->data.fd, cache->data, DSO__DATA_CACHE_SIZE);
if (ret <= 0) if (ret <= 0)
break; break;