Removed debug symbols from Newlib PNaCl toolchain.

Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

For my machine, reduced total build time from ~250 seconds to ~150 seconds.
Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483,#554
R=viettrungluu@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/65a713206fc07fc0f35647d2b2aa4d062f51ea31

[Sean Klein, 2015-11-20 01:14:57]

Description was changed from

==========
Removing debug symbols from Newlib PNaCl toolchain

BUG=#483
==========

to

==========
Removing debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

Reduced total build time from ~250 seconds to ~150 seconds.

Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

[Sean Klein, 2015-11-20 01:15:40]

Patchset #1 (id:1) has been deleted

[Sean Klein, 2015-11-20 01:16:12]

Description was changed from

==========
Removing debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

Reduced total build time from ~250 seconds to ~150 seconds.

Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

to

==========
Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

Reduced total build time from ~250 seconds to ~150 seconds.

Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

[Sean Klein, 2015-11-20 01:17:11]

Description was changed from

==========
Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

Reduced total build time from ~250 seconds to ~150 seconds.

Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

to

==========
Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

For my machine, reduced total build time from ~250 seconds to ~150 seconds.
Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

[Sean Klein, 2015-11-20 01:20:04]

smklein@chromium.org changed reviewers:
+ phosek@chromium.org, viettrungluu@chromium.org

[viettrungluu, 2015-11-20 21:41:02]

lgtm w/bug filed and noted

https://codereview.chromium.org/1461163003/diff/20001/build/toolchain/nacl/BU...
File build/toolchain/nacl/BUILD.gn (right):

https://codereview.chromium.org/1461163003/diff/20001/build/toolchain/nacl/BU...
build/toolchain/nacl/BUILD.gn:47: # TODO(smklein): Don't modify symbol_level
from the default value once
Could you file a bug for this, and add it to this TODO?

[Sean Klein, 2015-11-20 21:55:13]

Description was changed from

==========
Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

For my machine, reduced total build time from ~250 seconds to ~150 seconds.
Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483
==========

to

==========
Removed debug symbols from Newlib PNaCl toolchain.

Doing some preliminary profiling on the linking/optimizing
stages of PNaCl's toolchain, for an arbitrary pexe with
debug info enabled, pnacl-ld and pnacl-opt took roughly
equivalent time (For spinning cube, each stage took ~10-15
seconds). However, when stripping out debug info from
"./out/Debug/newlib_pnacl/spinning_cube.pexe.debug", I noticed
that even just removing debug info took a whopping 7 seconds.

Long story short: LLVM Debug info is bloated and slow in the
version used by PNaCl. It has since been improved
(source: https://www.youtube.com/watch?v=EgkZ8PTNSHQ), but updating
the LLVM version for PNaCl would be a nontrivial task.

For a shorter-term solution, when using the newlib_pnacl
toolchain, reduce the symbol level.

For my machine, reduced total build time from ~250 seconds to ~150 seconds.
Build times compared using goma, with a "cold" run done for each
before the measured time to warm goma's cache.

BUG=#483,#554
==========

[Sean Klein, 2015-11-20 22:05:02]

https://codereview.chromium.org/1461163003/diff/20001/build/toolchain/nacl/BU...
File build/toolchain/nacl/BUILD.gn (right):

https://codereview.chromium.org/1461163003/diff/20001/build/toolchain/nacl/BU...
build/toolchain/nacl/BUILD.gn:47: # TODO(smklein): Don't modify symbol_level
from the default value once
On 2015/11/20 21:41:02, viettrungluu wrote:
> Could you file a bug for this, and add it to this TODO?

Done.

[Sean Klein, 2015-11-20 22:07:15]

Committed patchset #2 (id:40001) manually as
65a713206fc07fc0f35647d2b2aa4d062f51ea31 (presubmit successful).