git blame with valgrind massif

I ran:
 valgrind --tool=massif --heap=yes git blame gcc/ChangeLog
it used about 2.25GB

How do you interpret the massif output?

Command: git blame gcc/ChangeLog

== 0 =========================== Heap allocation functions accounted for 98.2% of measured spacetime

Called from:
  34.3% : 0x44EFC2: patch_delta (git-compat-util.h:235)

  24.7% : 0x45DD38: cache_or_unpack_entry (git-compat-util.h:235)

  13.1% : 0x4909FC: xdl_cha_alloc (xutils.c:113)

  12.0% : 0x461277: strbuf_grow (git-compat-util.h:268)

   5.9% : 0x40EF5A: cmd_blame (git-compat-util.h:235)

   2.6% : 0x48FA5E: xdl_prepare_env (xprepare.c:79)

   1.9% : 0x45D775: unpack_compressed_entry (git-compat-util.h:235)

   1.5% : 0x452FE5: read_index_from (git-compat-util.h:284)

   1.3% : 0x48F672: xdl_prepare_ctx (xprepare.c:162)

  and 61 other insignificant places

== 1 ===========================
Context accounted for 34.3% of measured spacetime
  0x44EFC2: patch_delta (git-compat-util.h:235)

Called from:
  34.3% : 0x45DA03: unpack_entry (sha1_file.c:1578)

---------------------------------
Context accounted for 24.7% of measured spacetime
  0x45DD38: cache_or_unpack_entry (git-compat-util.h:235)

Called from:
  24.7% : 0x45F175: read_packed_sha1 (sha1_file.c:1815)

---------------------------------
Context accounted for 13.1% of measured spacetime
  0x4909FC: xdl_cha_alloc (xutils.c:113)

Called from:
   6.6% : 0x48F75B: xdl_prepare_ctx (xprepare.c:192)

   4.0% : 0x48F83A: xdl_prepare_ctx (xprepare.c:115)

---------------------------------
Context accounted for 12.0% of measured spacetime
  0x461277: strbuf_grow (git-compat-util.h:268)

Called from:
  12.0% : 0x4617F4: strbuf_read (strbuf.c:192)

  and 2 other insignificant places

---------------------------------
Context accounted for  5.9% of measured spacetime
  0x40EF5A: cmd_blame (git-compat-util.h:235)

Called from:
   5.9% : 0x40405A: handle_internal_command (git.c:266)

---------------------------------
Context accounted for  2.6% of measured spacetime
  0x48FA5E: xdl_prepare_env (xprepare.c:79)

Called from:
   2.6% : 0x48F21A: xdl_do_diff (xdiffi.c:332)

---------------------------------
Context accounted for  1.9% of measured spacetime
  0x45D775: unpack_compressed_entry (git-compat-util.h:235)

Called from:
   1.9% : 0x45D945: unpack_entry (sha1_file.c:1606)

  and 1 other insignificant place

---------------------------------
Context accounted for  1.5% of measured spacetime
  0x452FE5: read_index_from (git-compat-util.h:284)

Called from:
   1.5% : 0x40FAD7: cmd_blame (builtin-blame.c:2075)

---------------------------------
Context accounted for  1.3% of measured spacetime
  0x48F672: xdl_prepare_ctx (xprepare.c:162)

Called from:
   0.6% : 0x48FAAB: xdl_prepare_env (xprepare.c:280)

  and 1 other insignificant place

== 2 ===========================
Context accounted for 34.3% of measured spacetime
  0x44EFC2: patch_delta (git-compat-util.h:235)
  0x45DA03: unpack_entry (sha1_file.c:1578)

Called from:
  41.7% : 0x45D9BE: unpack_entry (sha1_file.c:1567)

  33.3% : 0x45F175: read_packed_sha1 (sha1_file.c:1815)

---------------------------------
Context accounted for 24.7% of measured spacetime
  0x45DD38: cache_or_unpack_entry (git-compat-util.h:235)
  0x45F175: read_packed_sha1 (sha1_file.c:1815)

Called from:
  24.7% : 0x45F55D: read_sha1_file (sha1_file.c:1881)

---------------------------------
Context accounted for  6.6% of measured spacetime
  0x4909FC: xdl_cha_alloc (xutils.c:113)
  0x48F75B: xdl_prepare_ctx (xprepare.c:192)

Called from:
   2.9% : 0x48FAAB: xdl_prepare_env (xprepare.c:280)

   1.6% : 0x48FAD0: xdl_prepare_env (xprepare.c:285)

---------------------------------
Context accounted for  4.0% of measured spacetime
  0x4909FC: xdl_cha_alloc (xutils.c:113)
  0x48F83A: xdl_prepare_ctx (xprepare.c:115)

Called from:
   4.0% : 0x48FAAB: xdl_prepare_env (xprepare.c:280)

  and 1 other insignificant place

---------------------------------
Context accounted for 12.0% of measured spacetime
  0x461277: strbuf_grow (git-compat-util.h:268)
  0x4617F4: strbuf_read (strbuf.c:192)

Called from:
  12.0% : 0x461881: strbuf_read_file (strbuf.c:228)

---------------------------------
Context accounted for  5.9% of measured spacetime
  0x40EF5A: cmd_blame (git-compat-util.h:235)
  0x40405A: handle_internal_command (git.c:266)

Called from:
   5.9% : 0x4045C9: main (git.c:456)

---------------------------------
Context accounted for  2.6% of measured spacetime
  0x48FA5E: xdl_prepare_env (xprepare.c:79)
  0x48F21A: xdl_do_diff (xdiffi.c:332)

Called from:
   2.6% : 0x48F3B0: xdl_diff (xdiffi.c:542)

---------------------------------
Context accounted for  1.9% of measured spacetime
  0x45D775: unpack_compressed_entry (git-compat-util.h:235)
  0x45D945: unpack_entry (sha1_file.c:1606)

Called from:
   2.4% : 0x45F175: read_packed_sha1 (sha1_file.c:1815)

  and 1 other insignificant place

---------------------------------
Context accounted for  1.5% of measured spacetime
  0x452FE5: read_index_from (git-compat-util.h:284)
  0x40FAD7: cmd_blame (builtin-blame.c:2075)

Called from:
   1.5% : 0x40405A: handle_internal_command (git.c:266)

---------------------------------
Context accounted for  0.6% of measured spacetime
  0x48F672: xdl_prepare_ctx (xprepare.c:162)
  0x48FAAB: xdl_prepare_env (xprepare.c:280)

Called from:
   0.6% : 0x48F21A: xdl_do_diff (xdiffi.c:332)

=================================

End of information.  Rerun with a bigger --depth value for more.