lkml.org 
[lkml]   [2018]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] perf stat: Add support for s390 transaction counters
Hi,

On Wed, Mar 14, 2018 at 08:43:17AM -0700, Andi Kleen wrote:
> > S390 has no support for Elision and uses transaction begin/end/abort
> > instructions. The CPU measurement counter facility provides counters for
> > transaction end and transaction abort.
>
> You don't need to implement the el-* events.
>
> > I have used this table (taken from arch/x86/events/intel/core.c) as giudeline:
> > /* Haswell special events */
> > EVENT_ATTR_STR(tx-start, tx_start, "event=0xc9,umask=0x1");
> > EVENT_ATTR_STR(tx-commit, tx_commit, "event=0xc9,umask=0x2");
> > EVENT_ATTR_STR(tx-abort, tx_abort, "event=0xc9,umask=0x4");
> > EVENT_ATTR_STR(tx-capacity, tx_capacity, "event=0x54,umask=0x2");
> > EVENT_ATTR_STR(tx-conflict, tx_conflict, "event=0x54,umask=0x1");
> > EVENT_ATTR_STR(el-start, el_start, "event=0xc8,umask=0x1");
> > EVENT_ATTR_STR(el-commit, el_commit, "event=0xc8,umask=0x2");
> > EVENT_ATTR_STR(el-abort, el_abort, "event=0xc8,umask=0x4");
> > EVENT_ATTR_STR(el-capacity, el_capacity, "event=0x54,umask=0x2");
> > EVENT_ATTR_STR(el-conflict, el_conflict, "event=0x54,umask=0x1");
> > EVENT_ATTR_STR(cycles-t, cycles_t, "event=0x3c,in_tx=1");
> > EVENT_ATTR_STR(cycles-ct, cycles_ct, "event=0x3c,in_tx=1,in_tx_cp=1");
> >
> >
> > So s390 can only support tx_commit and tx-abort symbolic names.

In detail, for s390 we have:

cpum_cf/TX_C_TABORT_NO_SPECIAL/
cpum_cf/TX_C_TABORT_SPECIAL/
cpum_cf/TX_C_TEND/
cpum_cf/TX_NC_TABORT/
cpum_cf/TX_NC_TEND/

The mapping of the above is not that easy. As s390 have counters for
non-constraint (TC_NC_*) and contraint (TX_C_*) transaction commits (TEND)
and aborts (TABORTs).

> We could change perf stat to fall back to only tx commit and tx abort.
> We already did that for one limited case.

Displaying these different types for s390 is important from my point of
view. Of course, I could create a mapping of TX_NC_TABORT/TX_NC_TEND
to tx-commit/tx-abort. The remaining events would still appear to be specific
to the cpum_cf.

So I would propose to go with adding the cpum_cf/ specific ones first.
If necessary, they could go into the perf/arch/s390/ directory and included
in builtin-stat. I put a todo on my list to provide at least a
tx-commit/abort for the nonconstraint transactions. (The other would still be
specific).

Kind regards,
Hendrik

--
Hendrik Brueckner
brueckner@linux.vnet.ibm.com | IBM Deutschland Research & Development GmbH
Linux on z Systems Development | Schoenaicher Str. 220, 71032 Boeblingen


IBM Deutschland Research & Development GmbH
Vorsitzender des Aufsichtsrats: Martina Koederitz
Geschaeftsfuehrung: Dirk Wittkopp
Sitz der Gesellschaft: Boeblingen
Registergericht: Amtsgericht Stuttgart, HRB 243294

\
 
 \ /
  Last update: 2018-03-14 17:43    [W:0.087 / U:0.844 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site