On 03/31/2017 07:03 PM, Stephane Eranian wrote: > Hi, > > > On Thu, Mar 23, 2017 at 8:31 AM, William Cohen <wco...@redhat.com> wrote: >> >> Hi Stephane, >> >> There is ABI change between libpfm-4.7 and libpfm-4.8 that is visible >> to programs using libpfm that break compatability. This change can be >> observed with libabigail's abidiff command >> (https://sourceware.org/libabigail/manual/abidiff.html) I found that >> following patch has changed the layout of struct pfm_event_attr_info_t >> in pfmlib.h: >> >> commit 4dc4c6ada254f30eee8cd2ae27bb0869a111b613 >> Author: Stephane Eranian <eran...@gmail.com> >> Date: Sat May 28 03:49:04 2016 +0200 >> >> Allow raw umask for OFFCORE_RESPONSE on Intel core PMUs >> >> This patch makes it possible to specify the raw umask as >> hexadecimal for the Intel core PMU OFFCORE_RESPONSE_* event. >> This makes it possible to encode a umask which could have been >> omitted by mistake from the library or not yet supported. >> >> $ examples/check_events offcore_response_0:0xffff >> >> Added validation tests for this new support. >> >> Signed-off-by: Stephane Eranian <eran...@gmail.com> >> >> --------------------------- include/perfmon/pfmlib.h >> --------------------------- >> index 24a2a60..8921164 100644 >> @@ -420,8 +420,8 @@ typedef struct { >> size_t size; /* struct sizeof */ >> uint64_t code; /* attribute code */ >> pfm_attr_t type; /* attribute type */ >> - int idx; /* attribute opaque index */ >> - pfm_attr_ctrl_t ctrl; /* what is providing attr */ >> + uint64_t idx; /* attribute opaque index */ >> + pfm_attr_ctrl_t ctrl; /* what is providing attr */ >> struct { >> unsigned int is_dfl:1; /* is default umask */ >> unsigned int is_precise:1; /* Intel X86: supports PEBS >> */ >> >> >> >> The struct in libpfm-4.7 is >> >> typedef struct { >> const char *name; /* attribute symbolic name */ >> const char *desc; /* attribute description */ >> const char *equiv; /* attribute is equivalent to */ >> size_t size; /* struct sizeof */ >> uint64_t code; /* attribute code */ >> pfm_attr_t type; /* attribute type */ >> int idx; /* attribute opaque index */ >> pfm_attr_ctrl_t ctrl; /* what is providing attr */ >> struct { >> unsigned int is_dfl:1; /* is default umask */ >> unsigned int is_precise:1; /* Intel X86: supports PEBS >> */ >> unsigned int reserved_bits:30; >> } SWIG_NAME(flags); >> union { >> uint64_t dfl_val64; /* default 64-bit value */ >> const char *dfl_str; /* default string value */ >> int dfl_bool; /* default boolean value */ >> int dfl_int; /* default integer value */ >> } SWIG_NAME(defaults); >> } pfm_event_attr_info_t; >> >> The patch changes idx from a 32-bit to 64-bit value. This causes >> padding (made explicit by commit >> 06b296c72838be44d8950dc03227fe0dc8ca1fb1) to be inserted so idx and >> following fields are at different locations in the struct. The struct >> is also made 8 bytes larger (512 bits to 576 bits). >> > Ok, my bad. That was not my goal here. > We can revert this change. But to enable support, this struct will > need to change. > So it will incur some ABI change.
Hi Stephane, Yes, limiting the idx to 32-bit will prevent a number of offcore events from working properly. In the comment it says "/* attribute opaque index */" for idx. Would it be possible to make that an index into a table of raw umask values? -Will > >> >> abidiff /usr/lib64/libpfm.so.4.7.0 libpfm.so >> ... >> [C]'function int pfm_get_event_attr_info(int, int, pfm_os_t, >> pfm_event_attr_info_t*)' at pfmlib_common.c:1812:1 has some indirect >> sub-type changes: >> parameter 4 of type 'pfm_event_attr_info_t*' has sub-type changes: >> in pointed to type 'typedef pfm_event_attr_info_t' at pfmlib.h:507:1: >> underlying type 'struct __anonymous_struct__' at pfmlib.h:486:1 >> changed: >> type size changed from 512 to 576 bits >> 1 data member insertion: >> 'int __anonymous_struct__::pad', at offset 352 (in bits) at >> pfmlib.h:493:1 >> 3 data member changes: >> type of 'int __anonymous_struct__::idx' changed: >> entity changed from 'int' to compatible type 'typedef uint64_t' >> at stdint.h:55:1 >> type name changed from 'int' to 'unsigned long int' >> type size changed from 32 to 64 bits >> and offset changed from 352 to 384 (in bits) >> 'pfm_attr_ctrl_t __anonymous_struct__::ctrl' offset changed from >> 384 to 448 (in bits) >> '__anonymous_struct__ ' offset changed from 416 to 480 (in bits) >> >> ... >> >> -Will ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
