From: Stephane Eranian <eranian@google.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@elte.hu, acme@redhat.com,
robert.richter@amd.com, ming.m.lin@intel.com,
andi@firstfloor.org, asharma@fb.com, ravitillo@lbl.gov,
vweaver1@eecs.utk.edu, khandual@linux.vnet.ibm.com,
dsahern@gmail.com
Subject: [PATCH v5 16/18] perf: enable reading of perf.data files from different ABI rev
Date: Thu, 2 Feb 2012 13:54:46 +0100 [thread overview]
Message-ID: <1328187288-24395-17-git-send-email-eranian@google.com> (raw)
In-Reply-To: <1328187288-24395-1-git-send-email-eranian@google.com>
This patch allows perf to process perf.data files generated
using an ABI that has a different perf_event_attr struct size, i.e.,
a different ABI version.
The perf_event_attr can be extended, yet perf needs to cope with
older perf.data files. Similarly, perf must be able to cope with
a perf.data file which is using a newer version of the ABI than
what it knows about.
This patch adds read_attr(), a routine that reads a perf_event_attr
struct from a file incrementally based on its advertised size. If
the on-file struct is smaller than what perf knows, then the extra
fields are zeroed. If the on-file struct is bigger, then perf only
uses what it knows about, the rest is skipped.
Signed-off-by: Stephane Eranian <eranian@google.com>
---
| 49 ++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 47 insertions(+), 2 deletions(-)
--git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 6f4187d..8d6c18d 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1959,6 +1959,51 @@ static int perf_header__read_pipe(struct perf_session *session, int fd)
return 0;
}
+static int read_attr(int fd, struct perf_header *ph,
+ struct perf_file_attr *f_attr)
+{
+ struct perf_event_attr *attr = &f_attr->attr;
+ size_t sz, left;
+ size_t our_sz = sizeof(f_attr->attr);
+ int ret;
+
+ memset(f_attr, 0, sizeof(*f_attr));
+
+ /* read minimal guaranteed structure */
+ ret = readn(fd, attr, PERF_ATTR_SIZE_VER0);
+ if (ret <= 0)
+ return -1;
+
+ /* on file perf_event_attr size */
+ sz = attr->size;
+ if (ph->needs_swap)
+ sz = bswap_32(sz);
+
+ if (sz == 0) {
+ /* assume ABI0 */
+ sz = PERF_ATTR_SIZE_VER0;
+ } else if (sz > our_sz) {
+ /* bigger than what we know about */
+ sz = our_sz;
+
+ /* skip what we do not know about */
+ lseek(fd, SEEK_CUR, attr->size - our_sz);
+ }
+ /* what we have not yet read and that we know about */
+ left = sz - PERF_ATTR_SIZE_VER0;
+ if (left) {
+ void *ptr = attr;
+ ptr += PERF_ATTR_SIZE_VER0;
+
+ ret = readn(fd, ptr, left);
+ if (ret <= 0)
+ return -1;
+ }
+ /* read the ids */
+ ret = readn(fd, &f_attr->ids, sizeof(struct perf_file_section));
+ return ret <= 0 ? -1 : 0;
+}
+
int perf_session__read_header(struct perf_session *session, int fd)
{
struct perf_header *header = &session->header;
@@ -1979,14 +2024,14 @@ int perf_session__read_header(struct perf_session *session, int fd)
return -EINVAL;
}
- nr_attrs = f_header.attrs.size / sizeof(f_attr);
+ nr_attrs = f_header.attrs.size / f_header.attr_size;
lseek(fd, f_header.attrs.offset, SEEK_SET);
for (i = 0; i < nr_attrs; i++) {
struct perf_evsel *evsel;
off_t tmp;
- if (readn(fd, &f_attr, sizeof(f_attr)) <= 0)
+ if (read_attr(fd, header, &f_attr) < 0)
goto out_errno;
if (header->needs_swap)
--
1.7.4.1
next prev parent reply other threads:[~2012-02-02 12:57 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-02 12:54 [PATCH v5 00/18] perf: add support for sampling taken branches Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 01/18] perf: add generic taken branch sampling support Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 02/18] perf: add Intel LBR MSR definitions Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 03/18] perf: add Intel X86 LBR sharing logic Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 04/18] perf: sync branch stack sampling with X86 precise_sampling Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 05/18] perf: add Intel X86 LBR mappings for PERF_SAMPLE_BRANCH filters Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 06/18] perf: disable LBR support for older Intel Atom processors Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 07/18] perf: implement PERF_SAMPLE_BRANCH for Intel X86 Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 08/18] perf: add LBR software filter support " Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 09/18] perf: disable PERF_SAMPLE_BRANCH_* when not supported Stephane Eranian
2012-02-06 19:23 ` Peter Zijlstra
2012-02-06 19:59 ` Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 10/18] perf: add hook to flush branch_stack on context switch Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 11/18] perf: add code to support PERF_SAMPLE_BRANCH_STACK Stephane Eranian
2012-02-06 18:06 ` Arnaldo Carvalho de Melo
2012-02-07 14:11 ` Stephane Eranian
2012-02-07 15:21 ` Arnaldo Carvalho de Melo
2012-02-02 12:54 ` [PATCH v5 12/18] perf: add support for sampling taken branch to perf record Stephane Eranian
2012-02-06 18:08 ` Arnaldo Carvalho de Melo
2012-02-02 12:54 ` [PATCH v5 13/18] perf: add support for taken branch sampling to perf report Stephane Eranian
2012-02-06 18:14 ` Arnaldo Carvalho de Melo
2012-02-02 12:54 ` [PATCH v5 14/18] perf: fix endianness detection in perf.data Stephane Eranian
2012-02-06 18:17 ` Arnaldo Carvalho de Melo
2012-02-06 18:18 ` Stephane Eranian
2012-02-06 21:47 ` David Ahern
2012-02-06 22:06 ` Arnaldo Carvalho de Melo
2012-02-06 22:29 ` David Ahern
2012-02-07 14:13 ` Stephane Eranian
2012-02-07 14:38 ` Arnaldo Carvalho de Melo
2012-02-17 9:42 ` [tip:perf/core] perf tools: " tip-bot for Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 15/18] perf: add ABI reference sizes Stephane Eranian
2012-02-02 12:54 ` Stephane Eranian [this message]
2012-02-06 18:19 ` [PATCH v5 16/18] perf: enable reading of perf.data files from different ABI rev Arnaldo Carvalho de Melo
2012-02-06 18:22 ` Arnaldo Carvalho de Melo
2012-02-07 7:03 ` Anshuman Khandual
2012-02-07 14:52 ` Arnaldo Carvalho de Melo
2012-02-06 22:19 ` David Ahern
2012-02-07 15:50 ` Stephane Eranian
2012-02-07 16:41 ` David Ahern
2012-02-07 17:42 ` Stephane Eranian
2012-02-07 17:57 ` David Ahern
2012-02-02 12:54 ` [PATCH v5 17/18] perf: fix bug print_event_desc() Stephane Eranian
2012-02-02 12:54 ` [PATCH v5 18/18] perf: make perf able to read file from older ABIs Stephane Eranian
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